Probing Particle-Carbon/Binder Degradation Behavior in Fatigued Layered Cathode Materials through Machine Learning Aided Diffraction Tomography

Understanding how reaction heterogeneity impacts cathode materials during Li-ion battery (LIB) electrochemical cycling is pivotal for unraveling their electrochemical performance. Yet, experimentally verifying these reactions has proven to be a challenge. To address this, we employed scanning μ-XRD computed tomography to scrutinize Ni-rich layered LiNi0.6Co0.2Mn0.2O2 (NCM622) and Li-rich layered Li[Li0.2Ni0.2Mn0.6]O2 (LLNMO). By harnessing machine learning (ML) techniques, we scrutinized an extensive dataset of μ-XRD patterns, about 100,000 patterns per slice, to unveil the spatial distribution of crystalline structure and microstrain. Our experimental findings unequivocally reveal the distinct behavior of these materials. NCM622 exhibits structural degradation and lattice strain intricately linked to the size of secondary particles. Smaller particles and the surface of larger particles in contact with the carbon/binder matrix experience intensified structural fatigue after long-term cycling. Conversely, both the surface and bulk of LLNMO particles endure severe strain-induced structural degradation during high-voltage cycling, resulting in significant voltage decay and capacity fade. This work holds the potential to fine-tune the microstructure of advanced layered materials and manipulate composite electrode construction in order to enhance the performance of LIBs and beyond.

Boosting Multielectron Reaction Stability of Sodium Vanadium Phosphate by High-Entropy Substitution

Na3V2(PO4)3 (NVP) based on the multielectron reactions between V2+ and V5+ has been considered a promising cathode for sodium-ion batteries (SIBs). However, it still suffers from unsatisfactory stability, caused by the poor reversibility of the V5+/V4+ redox couple and structure evolution. Herein, we propos a strategy that combines high-entropy substitution and electrolyte optimization to boost the reversible multielectron reactions of NVP. The high reversibility of the V5+/V4+ redox couple and crystalline structure evolution are disclosed by in situ X-ray absorption near-edge structure spectra and in situ X-ray diffraction. Meanwhile, the electrochemical reaction kinetics of high-entropy substitution NVP (HE-NVP) can be further improved in the diglyme-based electrolyte. These enable HE-NVP to deliver a superior electrochemical performance (capacity retention of 93.1% after 2000 cycles; a large reversible capacity of 120 mAh g-1 even at 5.0 A g-1). Besides, the long cycle life and high power density of the HE-NVP∥natural graphite full-cell configuration demonstrated the superiority of HE-NVP cathode in SIBs. This work highlights that the synergism of high-entropy substitution and electrolyte optimization is a powerful strategy to enhance the sodium-storage performance of polyanionic cathodes for SIBs.

Formulating Local Environment of Oxygen Mitigates Voltage Hysteresis in Li-Rich Materials

Li-rich cathode materials have emerged as one of the most prospective options for Li-ion batteries owing to their remarkable energy density (>900 Wh kg-1). However, voltage hysteresis during charge and discharge process lowers the energy conversion efficiency, which hinders their application in practical devices. Herein, the fundamental reason for voltage hysteresis through investigating the O redox behavior under different (de)lithiation states is unveiled and it is successfully addressed by formulating the local environment of O2-. In Li-rich Mn-based materials, it is confirmed that there exists reaction activity of oxygen ions at low discharge voltage (<3.6 V) in the presence of TM-TM-Li ordered arrangement, generating massive amount of voltage hysteresis and resulting in a decreased energy efficiency (80.95%). Moreover, in the case where Li 2b sites are numerously occupied by TM ions, the local environment of O2- evolves, the reactivity of oxygen ions at low voltage is significantly inhibited, thus giving rise to the large energy conversion efficiency (89.07%). This study reveals the structure-activity relationship between the local environment around O2- and voltage hysteresis, which provides guidance in designing next-generation high-performance cathode materials.

Negative Lattice Expansion in an O3-Type Transition-Metal Oxide Cathode for Highly Stable Sodium-Ion Batteries

The sodium extraction/insertion in layered transition-metal oxide (TMO) cathode materials are typically accompanied by slab sliding and lattice changes, leading to microstructure destruction and capacity decay. Herein, negative lattice expansion is observed in an O3 type Ni-based layered cathode of Na0.9 Ni0.32 Zn0.08 Fe0.1 Mn0.3 Ti0.2 O2 upon Na+ extraction. It is attributed to the weak Zn2+ -O2- orbital hybridization and increased electron density of the surrounding oxygen for reinforced interlayer O-O repulsive force. This enables gliding of TMO slabs for the intergrowth phase transition of P3→OP2 to alleviate lattice strain with moderate lattice shrinkage, which exhibits general interslab spacings and volume changes as low as 2.4 % and 1.9 %, respectively. The strong Ti-O bonds accommodate the internal distortion of TMO6 octahedra due to the flexibility of TiO6 octahedra during cycling. These endow a high specific capacity of 144.9 mAh g-1 and excellent cycling performance of pouch-type sodium-ion batteries with 93 % capacity retention after 3600 cycles.

Insights into the Phase Purity and Storage Mechanism of Nonstoichiometric Na3.4 Fe2.4 (PO4 )1.4 P2 O7 Cathode for High-Mass-Loading and High-Power-Density Sodium-Ion Batteries

Mixed-anion-group Fe-based phosphate materials, such as Na4 Fe3 (PO4 )2 P2 O7 , have emerged as promising cathode materials for sodium-ion batteries (SIBs). However, the synthesis of pure-phase material has remained a challenge, and the phase evolution during sodium (de)intercalation is debating as well. Herein, a solid-solution strategy is proposed to partition Na4 Fe3 (PO4 )2 P2 O7 into 2NaFePO4  ⋅ Na2 FeP2 O7 from the angle of molecular composition. Via regulating the starting ratio of NaFePO4 and Na2 FeP2 O7 during the synthesis process, the nonstoichiometric pure-phase material could be successfully synthesized within a narrow NaFePO4 content between 1.6 and 1.2. Furthermore, the proposed synthesis strategy demonstrates strong applicability that helps to address the impurity issue of Na4 Co3 (PO4 )2 P2 O7 and nonstoichiometric Na3.4 Co2.4 (PO4 )1.4 P2 O7 are evidenced to be the pure phase. The model Na3.4 Fe2.4 (PO4 )1.4 P2 O7 cathode (the content of NaFePO4 equals 1.4) demonstrates exceptional sodium storage performances, including ultrahigh rate capability under 100 C and ultralong cycle life over 14000 cycles. Furthermore, combined measurements of ex situ nuclear magnetic resonance, in situ synchrotron radiation diffraction and X-ray absorption spectroscopy clearly reveal a two-phase transition during Na+ extraction/insertion, which provides a new insight into the ionic storage process for such kind of mixed-anion-group Fe-based phosphate materials and pave the way for the development of high-power sodium-ion batteries.

Self-reporting and Biodegradable Thermosetting Solid Polymer Electrolyte

To date, significant efforts have been dedicated to improve their ionic conductivity, thermal stability, and mechanical strength of solid polymer electrolytes (SPEs). However, direct monitoring of physical and chemical changes in SPEs is still lacking. Moreover, existing thermosetting SPEs are hardly degradable. Herein, by overcoming the limitation predicted by Flory theory, self-reporting and biodegradable thermosetting hyperbranched poly(β-amino ester)-based SPEs (HPAE-SPEs) are reported. HPAE is successfully synthesized through a well-controlled "A2+B4" Michael addition strategy and then crosslinked it in situ to produce HPAE-SPEs. The multiple tertiary aliphatic amines at the branching sites confer multicolour luminescence to HPAE-SPEs, enabling direct observation of its physical and chemical damage. After use, HPAE-SPEs can be rapidly hydrolysed into non-hazardous β-amino acids and polyols via self-catalysis. Optimized HPAE-SPE exhibits an ionic conductivity of 1.3×10-4  S/cm at 60 °C, a Na+ transference number (t N a + ${{t}_{Na}^{+}}$ ) of 0.67, a highly stable sodium plating-stripping behaviour and a low overpotential of ≈190 mV. This study establishes a new paradigm for developing SPEs by engineering multifunctional polymers. The self-reporting and biodegradable properties would greatly expand the scope of applications for SPEs.

Oxygen Vacancies Driven by Co in the Deeply Charged State Inducing Intragranular Cracking of Ni-Rich Cathodes

Intragranular cracking within the material structure of Ni-rich (LiNix Coy Mn1 - x - y , x ≥0.9) cathodes greatly threatens cathode integrity and causes capacity degradation, yet its atomic-scale incubation mechanism is not completely elucidated. Notably, the physicochemical properties of component elements fundamentally determine the material structure of cathodes. Herein, a diffusion-controlled incubation mechanism of intragranular cracking is unraveled, and an underlying correlation model with Co element is established. Multi-dimensional analysis reveals that oxygen vacancies appear due to the charge compensation from highly oxidizing Co ions in the deeply charged state, driving the transition metal migration to Li layer and layered to rock-salt phase transition. The local accumulation of two accompanying tensile strains collaborates to promote the nucleation and growth of intragranular cracks along the fragile rock-salt phase domain on (003) plane. This study focuses on the potential risks posed by Co to the architectural and thermal stability of Ni-rich cathodes and is dedicated to the compositional design and performance optimization of Ni-rich cathodes.

Improving Low-temperature Performance and Stability of Na2 Ti6 O13 Anodes by the Ti-O Spring Effect through Nb-doping

Na2 Ti6 O13 (NTO) with high safety has been regarded as a promising anode candidate for sodium-ion batteries. In the present study, integrated modification of migration channels broadening, charge density re-distribution, and oxygen vacancies regulation are realized in case of Nb-doping and have obtained significantly enhanced cycling performance with 92 % reversible capacity retained after 3000 cycles at 3000 mA g-1 . Moreover, unexpected low-temperature performance with a high discharge capacity of 143 mAh g-1 at 100 mA g-1 under -15 °C is also achieved in the full cell. Theoretical investigation suggests that Nb preferentially replaces Ti3 sites, which effectively improves structural stability and lowers the diffusion energy barrier. What's more important, both the in situ X-ray diffraction (XRD) and in situ Raman furtherly confirm the robust spring effect of the Ti-O bond, making special charge compensation mechanism and respective regulation strategy to conquer the sluggish transport kinetics and low conductivity, which plays a key role in promoting electrochemical performance.

Electrochemical Investigation of Calcium Substituted Monoclinic Li3 V2 (PO4 )3 Negative Electrode Materials for Sodium- and Potassium-Ion Batteries

Herein, the electrochemical properties and reaction mechanism of Li3-2 x Cax V2 (PO4 )3 /C (x = 0, 0.5, 1, and 1.5) as negative electrode materials for sodium-ion/potassium-ion batteries (SIBs/PIBs) are investigated. All samples undergo a mixed contribution of diffusion-controlled and pseudocapacitive-type processes in SIBs and PIBs via Trasatti Differentiation Method, while the latter increases with Ca content increase. Among them, Li3 V2 (PO4 )3 /C exhibits the highest reversible capacity in SIBs and PIBs, while Ca1.5 V2 (PO4 )3 /C shows the best rate performance with a capacity retention of 46% at 20 C in SIBs and 47% at 10 C in PIBs. This study demonstrates that the specific capacity of this type of material in SIBs and PIBs does not increase with the Ca-content as previously observed in lithium-ion system, but the stability and performance at a high C-rate can be improved by replacing Li+ with Ca2+ . This indicates that the insertion of different monovalent cations (Na+ /K+ ) can strongly influence the redox reaction and structure evolution of the host materials, due to the larger ion size of Na+ and K+ and their different kinetic properties with respect to Li+ . Furthermore, the working mechanism of both LVP/C and Ca1.5 V2 (PO4 )3 /C in SIBs are elucidated via in operando synchrotron diffraction and in operando X-ray absorption spectroscopy.

Electrochemical Enhancement of Lithium-Ion Diffusion in Polypyrrole-Modified Sulfurized Polyacrylonitrile Nanotubes for Solid-to-Solid Free-Standing Lithium-Sulfur Cathodes

The energy density of lithium-sulfurized polyacrylonitrile (Li-SPAN) batteries has chronically suffered from low sulfur content. Although a free-standing electrode can significantly reduce noncapacity mass contribution, the slow bulk reaction kinetics still constrain the electrochemical performance. In this regard, a novel electrochemically active additive, polypyrrole (PPy), is introduced to construct PAN nanotubes as a sulfur carrier. This hollow channel greatly facilitates charge transport within the electrode and increases the sulfur content. Both electrochemical tests and simulations show that the SPANPPy-1% cathode possesses a larger lithium-ion diffusion coefficient and a more homogeneous phase interface than the SPAN cathode. Consequently, significantly improved capabilities and rate properties are achieved, as well as decent exportations under high-sulfur-loading or lean-electrolyte conditions. In-situ and semi-situ characterizations are further performed to demonstrate the nucleation growth of lithium sulfide and the evolution of the electrode surface structure. This type of electrochemically active additive provides a well-supported implementation of high-energy-density Li-S batteries.

Boosting the Ultrastable High-Na-Content P2-type Layered Cathode Materials with Zero-Strain Cation Storage via a Lithium Dual-Site Substitution Approach

P2-type layered transition-metal (TM) oxides, NaxTMO2, are highly promising as cathode materials for sodium-ion batteries (SIBs) due to their excellent rate capability and affordability. However, P2-type NaxTMO2 is afflicted by issues such as Na+/vacancy ordering and multiple phase transitions during Na-extraction/insertion, leading to staircase-like voltage profiles. In this study, we employ a combination of high Na content and Li dual-site substitution strategies to enhance the structural stability of a P2-type layered oxide (Na0.80Li0.024[Li0.065Ni0.22Mn0.66]O2). The experimental results reveal that these approaches facilitate the oxidation of Mn ions to a higher valence state, thereby affecting the local environment of both TM and Na ions. The resulting modification in the local structure significantly improves the Na-ion storage capabilities as required for cathode materials in SIBs. Furthermore, it induces a solid-solution reaction and enables nearly zero-strain operation (ΔV = 0.7%) in the Na0.80Li0.024[Li0.065Ni0.22Mn0.66]O2 cathode during cycling. The assembled full cells demonstrate an exceptional rate performance, with a retention rate of 87% at 10 C compared to that of 0.1 C, as well as an ultrastable cycling capability, maintaining a capacity retention of 73% at 2 C after 1000 cycles. These findings offer valuable insights into the electronic and structural chemistry of ultrastable cathode materials with "zero-strain" Na-ion storage.

[Review and perspective of clinical research involving chest tightness variant asthma in China]

Chest tightness variant asthma (CTVA) was first reported and named by Chinese scholars in 2013. It is a new clinical type of asthma characterized by chest tightness as the only or primary symptom, without typical asthma manifestations such as recurrent wheezing and shortness of breath, and without wheezing sounds heard during lung auscultation. The overall epidemiological data on CTVA is currently unavailable. Its pathogenesis is similar to that of typical asthma, involving eosinophilic airway inflammation. Due to the lack of typical clinical manifestations, insufficient knowledge of this disease in some clinicians and some other reasons, CTVA is susceptible to misdiagnosis or missed diagnosis. Currently, the diagnostic criteria for CTVA are: chest tightness as the only or primary symptom, without typical asthma symptoms and signs such as wheezing and shortness of breath, and with any one of the objective indicators of variable airflow limitation. Effective anti-asthma treatment is required, and other diseases that cause chest tightness, such as cardiovascular, digestive, nervous, muscular, and mental diseases should be excluded. CTVA treatment follows that of typical asthma, but the specific treatment duration is uncertain and may require long-term management. Traditional Chinese medicine has shown some therapeutic effects on CTVA. Most CTVA patients have a good prognosis after active anti-asthma treatment. This paper analyzes and summarizes the research of CTVA in China from 2013 and provides new perspectives for further exploration of CTVA.

[Investigation on cognition, diagnosis and treatment status of chest tightness variant asthma among Chinese pediatricians]

Objective: To evaluate the awareness, diagnosis and treatment of chest tightness variant asthma (CTVA) among pediatricians in China. Methods: The survey was conducted by convenient sampling method. Pediatricians with professional title of attending physician and above from different grades hospitals in 30 provinces were invited to conduct online questionnaire surveys through WeChat, pediatricians scan QR codes to complete electronic questionnaires in the mini program from January 16th to February 4th, 2021. The contents of questionnaire included the awareness, diagnosis and treatment of CTVA, and comparing the differences between pediatricians in secondary hospitals and tertiary hospitals. Results: A total of 1 529 pediatricians participated in the survey, and 1 484 (97.06%) pediatricians completed the questionnaire and included in the analysis, including 420 males (28.30%). The awareness rate of CTVA among pediatricians was 77.83 % (1 155/1 484). Pediatricians in tertiary hospitals had higher rates of awareness of CTVA than pediatricians in secondary hospitals [81.86% (898/1 097) vs 66.41% (257/387), P<0.001] and had better execution of the guidelines [89.15% (978/1 097) vs 79.59% (308/387), P<0.001]. A total of 93.06 % (1 381/1 484) of pediatricians' first-line treatment included inhaled corticosteroids (ICS) for CTVA. Among them, a higher proportion of pediatricians in tertiary hospitals used ICS included regimens for first-line treatment of CTVA compared with pediatricians in secondary hospitals [94.90% (1 041/1 097) vs 87.86% (340/387), P<0.001]. The reported well control rate of CTVA was 32.08% (476/1 484), which was significantly lower in secondary hospitals than that in tertiary hospitals [17.31% (67/387) vs 37.28% (409/1 097), P<0.001]. Conclusion: Most pediatricians are well aware of CTVA, among which there is a certain gap in clinical practice between pediatricians in secondary hospitals and tertiary hospitals in terms of understanding, diagnosis, and treatment of CTVA.

Occupancy of orbitals and the quadrupole collectivity in 45Sc nucleus

In the present work, the Doppler Shift Attenuation method (DSAM) was used to analyze the observed lineshapes of transitions from excited states in ⁴⁵Sc, populated in the reaction ³⁶Ar + ¹²C at a beam energy of 145 MeV. The interpretation and comparison of the experimental results have been performed with large-scale shell model calculations, involving different interactions like: GX1A, GX1J, FPD6, KB3 and ZBM2. KB3 and FPD6 (present work) interactions in the negative parity states, and in positive parity states ZBM2 are most pre-eminent in reproducing the results, due to the large configuration space describing strong collective effects. Furthermore, the present work also looks at the details of the shell model helping in improving the understanding for the occupancy of orbitals. The present investigation suggests the observation of stronger collectivity for positive parity states over negative parity states with predicted enhanced collectivity of states in ⁴⁵Sc nucleus.

A Metal-Organic Framework Based Quasi-Solid-State Electrolyte Enabling Continuous Ion Transport for High-Safety and High-Energy-Density Lithium Metal Batteries

Solid-state lithium metal batteries are promising next-generation rechargeable energy storage systems. However, the poor compatibility of the electrode/electrolyte interface and the low lithium ion conductivity of solid-state electrolytes are key issues hindering the practicality of solid-state electrolytes. Herein, rational designed metal-organic frameworks (MOFs) with the incorporation of two types of ionic liquids (ILs) are fabricated as quasi-solid electrolytes. The obtained MOF-IL electrolytes offer continuous ion transport channels with the functional sulfonic acid groups serving as lithium ion hopping sites, which accelerate the Li⁺ transport both in the bulk and at the interfaces. The quasi-solid MOF-IL electrolytes exhibit competitive ionic conductivities of over 3.0 × 10^-4 S cm^-1 at room temperature, wide electrochemical windows over 5.2 V, and good interfacial compatibility, together with greatly enhanced Li⁺ transference numbers compared to the bare IL electrolyte. Consequently, the assembled quasi-solid Li metal batteries show either superior stability at low C rates or improved rate performance, related to the species of ILs. Overall, the quasi-solid MOF-IL electrolytes possess great application potential in high-safety and high-energy-density lithium metal batteries.

Accumulated Lattice Strain as an Intrinsic Trigger for the First-Cycle Voltage Decay in Li-Rich 3d Layered Oxides

Li- and Mn-rich layered oxides (LMLOs) are promising cathode materials for Li-ion batteries (LIBs) owing to their high discharge capacity of above 250 mA h g^-1. A high voltage plateau related to the oxidation of lattice oxygen appears upon the first charge, but it cannot be recovered during discharge, resulting in the so-called voltage decay. Disappearance of the honeycomb superstructure of the layered structure at a slow C-rate (e.g., 0.1 C) has been proposed to cause the first-cycle voltage decay. By comparing the structural evolution of Li[Li_0.2Ni_0.2Mn_0.6]O₂ (LLNMO) at various current densities, the operando synchrotron-based X-ray diffraction results show that the lattice strain in bulk LLNMO is continuously increased over cycling, resulting in the first-cycle voltage loss upon Li-ion insertion. Unlike the LLNMO, the accumulated average lattice strain of LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) and LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622) from the open-circuit voltage to 4.8 V could be released on discharge. These findings help to gain a deep understanding of the voltage decay in LMLOs.

Guest Ion-Dependent Reaction Mechanisms of New Pseudocapacitive Mg3 V4 (PO4 )6 /Carbon Composite as Negative Electrode for Monovalent-Ion Batteries

Polyanion-type phosphate materials, such as M₃ V₂ (PO₄ )₃ (M = Li/Na/K), are promising as insertion-type negative electrodes for monovalent-ion batteries including Li/Na/K-ion batteries (lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), and potassium-ion batteries (PIBs)) with fast charging/discharging and distinct redox peaks. However, it remains a great challenge to understand the reaction mechanism of materials upon monovalent-ion insertion. Here, triclinic Mg₃ V₄ (PO₄ )₆ /carbon composite (MgVP/C) with high thermal stability is synthesized via ball-milling and carbon-thermal reduction method and applied as a pseudocapacitive negative electrode in LIBs, SIBs, and PIBs. In operando and ex situ studies demonstrate the guest ion-dependent reaction mechanisms of MgVP/C upon monovalent-ion storage due to different sizes. MgVP/C undergoes an indirect conversion reaction to form Mg⁰ , V⁰ , and Li₃ PO₄ in LIBs, while in SIBs/PIBs the material only experiences a solid solution with the reduction of V³⁺ to V²⁺ . Moreover, in LIBs, MgVP/C delivers initial lithiation/delithiation capacities of 961/607 mAh g^-1 (30/19 Li⁺ ions) for the first cycle, despite its low initial Coulombic efficiency, fast capacity decay for the first 200 cycles, and limited reversible insertion/deinsertion of 2 Na⁺ /K⁺ ions in SIBs/PIBs. This work reveals a new pseudocapacitive material and provides an advanced understanding of polyanion phosphate negative material for monovalent-ion batteries with guest ion-dependent energy storage mechanisms.

Synergy of cations in high entropy oxide lithium ion battery anode

High entropy oxides (HEOs) with chemically disordered multi-cation structure attract intensive interest as negative electrode materials for battery applications. The outstanding electrochemical performance has been attributed to the high-entropy stabilization and the so-called 'cocktail effect'. However, the configurational entropy of the HEO, which is thermodynamically only metastable at room-temperature, is insufficient to drive the structural reversibility during conversion-type battery reaction, and the 'cocktail effect' has not been explained thus far. This work unveils the multi-cations synergy of the HEO Mg_0.2Co_0.2Ni_0.2Cu_0.2Zn_0.2O at atomic and nanoscale during electrochemical reaction and explains the 'cocktail effect'. The more electronegative elements form an electrochemically inert 3-dimensional metallic nano-network enabling electron transport. The electrochemical inactive cation stabilizes an oxide nanophase, which is semi-coherent with the metallic phase and accommodates Li⁺ ions. This self-assembled nanostructure enables stable cycling of micron-sized particles, which bypasses the need for nanoscale pre-modification required for conventional metal oxides in battery applications. This demonstrates elemental diversity is the key for optimizing multi-cation electrode materials.

Origin and Regulation of Interface Fusion during Synthesis of Single-Crystal Ni-Rich Cathodes

Interface fusion plays a key role in constructing Ni-based single-crystal cathodes, and is governed by the atomic migration related to kinetics. However, the interfacial atom migration path and its control factors are lack of clearly understanding. Herein, we systematically probe the solid-state synthesis mechanism of single-crystal LiNi_0.92 Co_0.04 Mn_0.04 O₂ , including the effects of precursor size, Li/transition metal (TM) ratio and sintering temperature on the structure. Multi-dimensional analysis unravels that thermodynamics drives interface atoms migration through intermediate state (i.e., cation mixing phase) to induce grain boundary fusion. Moreover, we demonstrate that smaller precursor size (<6 μm), lager Li/TM ratio (>1.0) and higher temperature (≥810 °C) are conducive to promote the growth of the intermediate state due to reaction kinetics enhancement, and ultimately strengthen the atomic migration-induced interface fusion.

Long-Range Cationic Disordering Induces two Distinct Degradation Pathways in Co-Free Ni-Rich Layered Cathodes

Ni-rich layered oxides are one of the most attractive cathode materials in high-energy-density lithium-ion batteries, their degradation mechanisms are still not completely elucidated. Herein, we report a strong dependence of degradation pathways on the long-range cationic disordering of Co-free Ni-rich Li_1-m (Ni_0.94 Al_0.06 )_1+m O₂ (NA). Interestingly, a disordered layered phase with lattice mismatch can be easily formed in the near-surface region of NA particles with very low cation disorder (NA-LCD, m≤0.06) over electrochemical cycling, while the layered structure is basically maintained in the core of particles forming a "core-shell" structure. Such surface reconstruction triggers a rapid capacity decay during the first 100 cycles between 2.7 and 4.3 V at 1 C or 3 C. On the contrary, the local lattice distortions are gradually accumulated throughout the whole NA particles with higher degrees of cation disorder (NA-HCD, 0.06≤m≤0.15) that lead to a slow capacity decay upon cycling.

A Disordered Rubik's Cube-Inspired Framework for Sodium-Ion Batteries with Ultralong Cycle Lifespan

Sodium-ion batteries (SIBs) with fast-charge capability and long lifespan could be applied in various sustainable energy storage systems, from personal devices to grid storage. Inspired by the disordered Rubik's cube, here, we report that the high-entropy (HE) concept can lead to a very substantial improvement in the sodium storage properties of hexacyanoferrate (HCF). An example of HE-HCF has been synthesized as a proof of concept, which has achieved impressive cycling stability over 50 000 cycles and an outstanding fast-charging capability up to 75 C. Remarkable air stability and all-climate performance are observed. Its quasi-zero-strain reaction mechanism and high sodium diffusion coefficient have been measured and analyzed by multiple in situ techniques and density functional theory calculations. This strategy provides new insights into the development of advanced electrodes and provides the opportunity to tune electrochemical performance by tailoring the atomic composition.

Reversible Metal and Ligand Redox Chemistry in Two-Dimensional Iron-Organic Framework for Sustainable Lithium-Ion Batteries

Metal-organic frameworks (MOFs) are emerging as attractive electrode materials for lithium-ion batteries, owing to their fascinating features of sustainable resources, tunable chemical components, flexible molecular skeletons, and renewability. However, they are faced with a limited number of redox-active sites and unstable molecular frameworks during electrochemical processes. Herein, we design a novel two-dimensional (2D) iron(III)-tetraamino-benzoquinone (Fe-TABQ) with dual redox centers of Fe cations and TABQ ligands for high-capacity and stable lithium storage. It is constructed of square-planar Fe-N₂O₂ linkages and phenylenediamine building blocks, between which the Fe-TABQ chains are connected by multiple hydrogen bonds, and then featured as an extended π-d-conjugated 2D structure. The redox chemistry of both Fe³⁺ cations and TABQ anions is revealed to render its remarkable specific capacity of 251.1 mAh g^-1. Benefiting from the intrinsic robust Fe-N(O) bonds and reinforced Li-N(O) bonds during cycling, Fe-TABQ delivers high capacity retentions over 95% after 200 cycles at various current densities. This work will enlighten more investigations for the molecular designs of advanced MOF-based electrode materials.

Homeostatic Solid Solution in Layered Transition-Metal Oxide Cathodes of Sodium-Ion Batteries

Two-phase transformation reaction is ubiquitous in solid-state electrochemistry; however, it usually involves inferior structure rearrangement upon extraction and insertion of large-sized Na⁺, thus leading to severe local strain, cracks, and capacity decay in sodium-ion batteries (SIBs). Here, a homeostatic solid solution reaction is reported in the layered cathode material P'2-Na_0.653Ni_0.081Mn_0.799Ti_0.120O₂ during sodiation and desodiation. It is induced by the synergistic incorporation of Ni and Ti for the reinforced O(2p)-Mn(3d-e_g*) hybridization, which leads to mitigated Jahn-Teller distortion of MnO₆ octahedra, contracted transition-metal oxide slabs, and enlarged Na layer spacings. The thermodynamically favorable solid solution pathway rewards the SIBs with excellent cycling stability (87.2% capacity retention after 500 cycles) and rate performance (100.5 mA h g^-1 at 2500 mA g^-1). The demonstrated reaction pathway will open a new avenue for rational designing of cathode materials for SIBs and beyond.

Prognostic Value of Four Preimplantation Malnutrition Estimation Tools in Predicting Heart Failure Hospitalization of the Older Diabetic Patients with Right Ventricular Pacing

OBJECTIVES

The prognostic value of preimplantation nutritional status is not yet known for older diabetic patients that received right ventricular pacing (RVP). The study aimed to investigate the clinical value of the four malnutrition screening tools for the prediction of heart failure hospitalization (HFH) in older diabetic patients that received RVP.

DESIGN

Retrospective observational cohort study.

SETTING AND PARTICIPANTS

This study was conducted between January 2017 and January 2018 at the Fuwai Hospital, Beijing, China, and included older (age ≥ 65 years) diabetic patients that received RVP for the first time Measurements: The Prognostic Nutritional Index (PNI), Geriatric Nutritional Risk Index (GNRI), Naples Prognostic Score (NPS), and the Controlling Nutritional Status (CONUT) score were used to estimate the preimplantation nutritional status of the patients. Univariate and multivariate Cox proportional hazard regression analyses were performed to investigate the association between preimplantation malnutrition and HFH.

RESULTS

Overall, 231 older diabetic patients receiving RVP were included. The median follow-up period after RVP was 53 months. HFH was reported for 19.9% of the included patients. Our results showed preimplantation malnutrition for 18.2%, 15.2%, 86.6% and 66.2% of the included patients based on the PNI, GNRI, NPS, and CONUT score, respectively. The cumulative rate of HFH during follow-up period was significantly higher for patients in the preimplantation malnutrition group based on the PNI (log-rank = 13.0, P = 0.001), GNRI (log-rank = 8.5, P = 0.01), and NPS (log-rank = 15.7, P < 0.001) compared to the normal nutrition group, but was not statistically significant for those in the preimplantation malnutrition group based on the CONUT score (log-rank = 2.7, P = 0.3). As continuous variables, all the nutritional indices showed significant correlation with HFH (all P < 0.05). However, multivariate analysis showed that only GNRI was independently associated with HFH (HR = 0.97, 95% CI: 0.937-0.997, P = 0.032). As categorical variables, PNI, GNRI, and NPS showed significant correlation with HFH. After adjustment of confounding factors, moderate-to-severe degree of malnutrition was an independent predictor of HFH based on the PNI (HR = 4.66, 95% CI: 1.03-21.00, P = 0.045) and GNRI (HR = 3.02, 95% CI: 1.02-9.00, P = 0.047).

CONCLUSION

Preimplantation malnutrition was highly prevalent in older diabetic patients that received RVP. The malnutrition prediction tools, PNI and GNRI, showed significant prognostic value in accurately predicting HFH in older diabetic patients with RVP.

Quasi-Solid-State Ion-Conducting Arrays Composite Electrolytes with Fast Ion Transport Vertical-Aligned Interfaces for All-Weather Practical Lithium-Metal Batteries

The rapid improvement in the gel polymer electrolytes (GPEs) with high ionic conductivity brought it closer to practical applications in solid-state Li-metal batteries. The combination of solvent and polymer enables quasi-liquid fast ion transport in the GPEs. However, different ion transport capacity between solvent and polymer will cause local nonuniform Li⁺ distribution, leading to severe dendrite growth. In addition, the poor thermal stability of the solvent also limits the operating-temperature window of the electrolytes. Optimizing the ion transport environment and enhancing the thermal stability are two major challenges that hinder the application of GPEs. Here, a strategy by introducing ion-conducting arrays (ICA) is created by vertical-aligned montmorillonite into GPE. Rapid ion transport on the ICA was demonstrated by ⁶Li solid-state nuclear magnetic resonance and synchrotron X-ray diffraction, combined with computer simulations to visualize the transport process. Compared with conventional randomly dispersed fillers, ICA provides continuous interfaces to regulate the ion transport environment and enhances the tolerance of GPEs to extreme temperatures. Therefore, GPE/ICA exhibits high room-temperature ionic conductivity (1.08 mS cm^-1) and long-term stable Li deposition/stripping cycles (> 1000 h). As a final proof, Li||GPE/ICA||LiFePO₄ cells exhibit excellent cycle performance at wide temperature range (from 0 to 60 °C), which shows a promising path toward all-weather practical solid-state batteries.

Structural Origin of Suppressed Voltage Decay in Single-Crystalline Li-Rich Layered Li[Li0.2 Ni0.2 Mn0.6 ]O2 Cathodes

Lithium- and manganese-rich layered oxides (LMLOs, ≥ 250 mAh g^-1 ) with polycrystalline morphology always suffer from severe voltage decay upon cycling because of the anisotropic lattice strain and oxygen release induced chemo-mechanical breakdown. Herein, a Co-free single-crystalline LMLO, that is, Li[Li_0.2 Ni_0.2 Mn_0.6 ]O₂ (LLNMO-SC), is prepared via a Li⁺ /Na⁺ ion-exchange reaction. In situ synchrotron-based X-ray diffraction (sXRD) results demonstrate that relatively small changes in lattice parameters and reduced average micro-strain are observed in LLNMO-SC compared to its polycrystalline counterpart (LLNMO-PC) during the charge-discharge process. Specifically, the as-synthesized LLNMO-SC exhibits a unit cell volume change as low as 1.1% during electrochemical cycling. Such low strain characteristics ensure a stable framework for Li-ion insertion/extraction, which considerably enhances the structural stability of LLNMO during long-term cycling. Due to these peculiar benefits, the average discharge voltage of LLNMO-SC decreases by only ≈0.2 V after 100 cycles at 28 mA g^-1 between 2.0 and 4.8 V, which is much lower than that of LLNMO-PC (≈0.5 V). Such a single-crystalline strategy offers a promising solution to constructing stable high-energy lithium-ion batteries (LIBs).

A Rational Biphasic Tailoring Strategy Enabling High-Performance Layered Cathodes for Sodium-Ion Batteries

Layered oxide cathodes usually exhibit high compositional diversity, thus providing controllable electrochemical performance for Na-ion batteries. These abundant components lead to complicated structural chemistry, closely affecting the stacking preference, phase transition and Na⁺ kinetics. With this perspective, we explore the thermodynamically stable phase diagram of various P2/O3 composites based on a rational biphasic tailoring strategy. Then a specific P2/O3 composite is investigated and compared with its monophasic counterparts. A highly reversible structural evolution of P2/O3-P2/O3/P3-P2/P3-P2/Z/O3'-Z/O3' based on the Ni²⁺ /Ni^3.5+ , Fe³⁺ /Fe⁴⁺ and Mn^3.8+ /Mn⁴⁺ redox couples upon sequential Na extraction/insertion is revealed. The reduced structural strain at the phase boundary alleviates the phase transition and decreases the lattice mismatch during cycling, endowing the biphasic electrode a large reversible capacity of 144 mAh g^-1 with the energy density approaching 514 Wh kg^-1 .

Streamline Sulfur Redox Reactions to Achieve Efficient Room-Temperature Sodium-Sulfur Batteries

It is vital to dynamically regulate S activity to achieve efficient and stable room-temperature sodium-sulfur (RT/Na-S) batteries. Herein, we report using cobalt sulfide as an electron reservoir to enhance the activity of sulfur cathodes, and simultaneously combining with cobalt single atoms as double-end binding sites for a stable S conversion process. The rationally constructed CoS₂ electron reservoir enables the straight reduction of S to short-chain sodium polysulfides (Na₂ S₄ ) via a streamlined redox path through electron transfer. Meanwhile, cobalt single atoms synergistically work with the electron reservoir to reinforce the streamlined redox path, which immobilize in situ formed long-chain products and catalyze their conversion, thus realizing high S utilization and sustainable cycling stability. The as-developed sulfur cathodes exhibit a superior rate performance of 443 mAh g^-1 at 5 A g^-1 with a high cycling capacity retention of 80 % after 5000 cycles at 5 A g^-1 .

[Initial clinical experience of left bundle branch pacing after transcatheter aortic valve implantation]

Objective: To investigate the efficacy and safety of left bundle branch pacing(LBBP) in patients after transcatheter aortic valve implantation (TAVI). Methods: This is a retrospective study. A total of 35 patients underwent TAVI and received pacemaker implantation from January 2018 to December 2020 in Beijing Fuwai Hospital were enrolled. Patients were divided into LBBP group (n=12) and right ventricular apex pacing (RVAP) group (n=23) according to the pacing position. The success rate of operation in LBBP group was calculated, and the occurrence of complications were observed, and the parameters of pacemaker were measured on the 3rd day and 1, 3 and 6 months after operation. The N-terminal pro-B-type natriuretic peptide (NT-proBNP), echocardiographic and ECG indexes were compared between the two groups on the 3rd day and 1, 3, and 6 months after pacemaker implantation. Result: A total of 35 patients were included, The age was (76.4±7.7) years, including 19 males (54.3%). The procedure time ((86.58±17.10)min vs. (68.74±9.18)min, P<0.001) and fluoroscopy duration ((20.08±4.44)min vs. (17.00±2.26)min, P<0.001) were significantly longer in LBBP group compared with RVAP group. The operation success rate of LBBP group was 11/12. There was no serious operation related complications such as pneumothorax, hemothorax, electrode dislocation, infection, and lower limb bleeding. The patients were followed up for 7.43 (5.21, 9.84) months. The programmed parameters of pacemaker were in the ideal range and stable during follow-up. At 3 and 6 months after operation, the left ventricular ejection fraction in LBBP group was higher than that in RVAP Group (at 3 months: (60.75±2.89)% vs. (57.35±3.33)%, P=0.004; at 6 months: (63.17±3.33)% vs. (56.17±3.97)%, P<0.001), NT-proBNP values was lower in LBBP group than that in RVAP Group (at 3 months: 822 (607, 1 150)ng/L vs. 1 052 (902, 1 536)ng/L, P=0.006; at 6 months: 440 (330,679)ng/L vs. 783 (588, 1 023)ng/L, P=0.001). At 1, 3 and 6 months after operation, the QRS duration was shorter in LBBP group than that in RVAP group (1 month: 99 (97, 107)ms vs. 126(124, 130)ms, P<0.001; 3 months: 98(96, 105)ms vs. 129(128, 133)ms, P<0.001; 6 months: 96(94, 104)ms vs. 130(128, 132)ms, P<0.001). Conclusions: For patients with permanent pacemaker indications after TAVI, LBBP is feasible, safe and reliable. It could improve the cardiac function in the short term, the long-term effect of LBBP needs to be further observed.

Activating a Multielectron Reaction of NASICON-Structured Cathodes toward High Energy Density for Sodium-Ion Batteries

The increasing demand to efficiently store and utilize the electricity from renewable energy resources in a sustainable way has boosted the request for sodium-ion battery technology due to the high abundance of sodium sources worldwide. Na superionic conductor (NASICON) structured cathodes with a robust polyanionic framework have been intriguing because of their open 3D structure and superior thermal stability. The ever-increasing demand for higher energy densities with NASICON-structured cathodes motivates us to activate multielectron reactions, thus utilizing the third sodium ion toward higher voltage and larger capacity, both of which have been the bottlenecks for commercializing sodium-ion batteries. A doping strategy with Cr inspired by first-principles calculations enables the activation of multielectron redox reactions of the redox couples V²⁺/V³⁺, V³⁺/V⁴⁺, and V⁴⁺/V⁵⁺, resulting in remarkably improved energy density even in comparison to the layer structured oxides and Prussian blue analogues. This work also comprehensively clarifies the role of the Cr dopant during sodium storage and the valence electron transition process of both V and Cr. Our findings highlight the importance of a broadly applicable doping strategy for achieving multielectron reactions of NASICON-type cathodes with higher energy densities in sodium-ion batteries.

Activating Inert Surface Pt Single Atoms via Subsurface Doping for Oxygen Reduction Reaction

The performance of single-atom catalysts strongly depends on their particular coordination environments in the near-surface region. Herein, we discover that engineering extra Pt single atoms in the subsurface (Pt_subsurf) can significantly enhance the catalytic efficiency of surface Pt single atoms toward the oxygen reduction reaction (ORR). We experimentally and theoretically investigated the effects of the Pt_subsurf single atoms implanted in different positions of the subsurface of Co particles. The local environments and catalytic properties of surface Pt₁ are highly tunable via Pt_subsurf doping. Specifically, the obtained Pt₁@Co/NC catalyst displays a remarkable performance for ORR, achieving mass activity of 4.2 mA μg_Pt^-1 (28 times higher than that of commercial Pt/C) at 0.9 V versus reversible hydrogen electrode (RHE) in 0.1 M HClO₄ solution with high stability over 30000 cycles.

New Insight into Desodiation/Sodiation Mechanism of MoS2: Sodium Insertion in Amorphous Mo-S Clusters

Molybdenum disulfide (MoS₂) is a promising anode material for sodium batteries due to its high theoretical capacity. While significantly improved electrochemical performance has been achieved, the reaction mechanism is still equivocal. Herein, we applied electron pair distribution function and X-ray absorption spectroscopy to investigate the desodiation/sodiation mechanism of MoS₂ electrodes. The results reveal that Mo-S bonds are well preserved and dominant in the sodiation product matrix but do not convert to metallic Mo and Na₂S even at deep sodiation. The MoS₂ multilayer sheets break into disordered MoS_x clusters with modified octahedral symmetry during discharging. The long-range order was not rebuilt during subsequent charging but with partial recovery of the Mo-S coordination symmetry. The mechanism of the reaction is independent of the carbon matrix, although it prevents the MoS_x clusters from leaching into the electrolyte and thus contributes to an extended cycle life. This work refreshes the fundamental understanding of the desodiation/sodiation mechanism of MoS₂ materials.

Superior sodium storage of Na3V(PO3)3N nanofibers as a high voltage cathode for flexible sodium-ion battery devices

The cathode materials for sodium-ion batteries are always the key issues for the ultimate success of large-scale energy storage systems. The nitrogen-dope polyanionic type material is one of the important high voltage candidates. Herein, we have developed a simple and facile method to synthesize a high voltage cathode material, Na₃V(PO₃)₃N nanofibers, via an electrospinning approach. Unexpected excellent rate performance and cyclability have been demonstrated, with a discharge capacity of 61.5 mAh g^-1achieved at a current density of 4 A g^-1. Capacity retention of 86.7% could be obtained at 0.8 A g^-1over 2000 cycles. Density functional theory calculations reveal that this material has an abnormal flat band characteristic, and its high voltage platform can be explained by the dominant V d-orbital contribution to the density of states at the Fermi level.

Comprehensive Investigation of a Slight Overcharge on Degradation and Thermal Runaway Behavior of Lithium-Ion Batteries

Overcharge is a hazardous abuse condition that has dominant influences on cell performance and safety. This work, for the first time, comprehensively investigates the impact of different overcharge degrees on degradation and thermal runaway behavior of lithium-ion batteries. The results indicate that single overcharge has little influence on cell capacity, while it severely degrades thermal stability. Degradation mechanisms are investigated by utilizing the incremental capacity-differential voltage and relaxation voltage analyses. During the slight overcharge process, the conductivity loss and the loss of lithium inventory always occur; the loss of active material starts happening only when the cell is overcharged to a certain degree. Lithium plating is the major cause for the loss of lithium inventory, and an interesting phenomenon that the arrival time of the dV/dt peak decreases linearly with the increase of the overcharge degree is found. The cells with different degrees of overcharge exhibit a similar behavior during adiabatic thermal runaway. Meanwhile, the relationship between sudden voltage drop and thermal runaway is further established. More importantly, the characteristic temperature of thermal runaway, especially the self-heating temperature (T₁), decreases severely along with overcharging, which means that a slight overcharge severely decreases the cell thermal stability. Further, post-mortem analysis is conducted to investigate the degradation mechanisms. The mechanism of the side reactions caused by a slight overcharge on the degradation performance and thermal runaway characteristics is revealed.

Dielectric Relaxation and Magnetic Structure of A-Site-Ordered Perovskite Oxide Semiconductor CaCu3Fe2Ta2O12

A new perovskite oxide semiconductor, CaCu₃Fe₂Ta₂O₁₂, was synthesized through a high-pressure and high-temperature approach. The compound possesses an Im3̅ space group, where it crystallizes to an A-site-ordered but B-site partial ordered quadruple perovskite structure. Spin ordering occurs around 150 K owing to the antiferromagnetic coupling between Fe³⁺ spins and ferromagnetic coupling between Cu²⁺ spins. The room-temperature dielectric permittivity of CaCu₃Fe₂Ta₂O₁₂ was measured to be approximately 2500 at 1 kHz. More importantly, isothermal frequency-dielectric spectroscopy demonstrates the existence of two dielectric relaxations. Debye-like relaxation is attributed to charge carriers trapped among the oxygen vacancies at low temperatures and Maxwell-Wagner polarization relaxation at high temperatures. CaCu₃Fe₂Ta₂O₁₂ is a new magnetic semiconductor, where A-site ordering is intercorrelated with second-order Jahn-Teller distortion. These findings offer opportunities to design novel perovskite oxides with attractive magnetic and dielectric properties.

New α-Emitting Isotope ^{214}U and Abnormal Enhancement of α-Particle Clustering in Lightest Uranium Isotopes

A new α-emitting isotope ^{214}U, produced by the fusion-evaporation reaction ^{182}W(^{36}Ar,4n)^{214}U, was identified by employing the gas-filled recoil separator SHANS and the recoil-α correlation technique. More precise α-decay properties of even-even nuclei ^{216,218}U were also measured in the reactions of ^{40}Ar, ^{40}Ca beams with ^{180,182,184}W targets. By combining the experimental data, improved α-decay reduced widths δ^{2} for the even-even Po-Pu nuclei in the vicinity of the magic neutron number N=126 are deduced. Their systematic trends are discussed in terms of the N_{p}N_{n} scheme in order to study the influence of proton-neutron interaction on α decay in this region of nuclei. It is strikingly found that the reduced widths of ^{214,216}U are significantly enhanced by a factor of two as compared with the N_{p}N_{n} systematics for the 84≤Z≤90 and N<126 even-even nuclei. The abnormal enhancement is interpreted by the strong monopole interaction between the valence protons and neutrons occupying the π1f_{7/2} and ν1f_{5/2} spin-orbit partner orbits, which is supported by the large-scale shell model calculation.

[The value of intraoperative cerebral oxygen saturation in predicting postoperative neurocognitive dysfunction in elderly patients with mild cognitive impairment]

Objective: To evaluate the value of intraoperative cerebral oxygen saturation in predicting postoperative neurocognitive dysfunction (PND) in elderly patients with mild cognitive impairment. Methods: A total of 210 cases of lumbar decompression, bone grafting and fusion surgery under general anesthesia were collected in the Third Central Hospital of Tianjin from June, 2019 to January, 2020, either sex, aged 65-75 year, BMI 19.5-32.5 kg/m(2), ASA physical status Ⅱ or Ⅲ, preoperative comorbidities with mild cognitive impairment. MoCA and MMSE were used to evaluate the cognitive function of patients 1 day before the operation, 7 days and 3 monthes after operation. PND group (n=38) and non-PND group (n=172) were selected according to postoperative MMSE and MoCA scale scores and the diagnostic criteria of PND. Heart rate (HR) , mean arterial pressure (MAP), pulse oxygen saturation (SpO(2)), bispectral index (BIS), cerebral tissue oxygen saturation (SctO(2), average left and right brain SctO(2) were recorded) were recorded pre-anesthetic (T(0)), ten minutes of anesthesia(T(1)), twenty minutes of anesthesia (T(2)), thirty minutes into the operation (T(3)), one hour into the operation (T(4)), end of the surgery (T(5)), and leave the PACU (T(6)). SctO(2) at time point T(0) was the base value of SctO(2), and the maximum percentage drop in SctO(2) from the base value was calculated (SctO(2max)%). Results: The incidence of PND was 18% (38/210) in 210 elderly patients undergoing surgery. The age of PND group and non-PND group was (71.0±2.1) and (67.8±2.0) years old, and the PACU time was (57±5) and (46±8) min, respectively. Compared with the non-PND group, the age of the PND group was higher (t=2.600, P<0.05) and the PACU time was longer (t=3.039, P<0.05). At the time points T(3), T(4), T(5) and T(6), SctO(2) in the PND group was (62±10) %, (60±11) %, (64±12) % and (66±10)%, respectively, lower than that in the non-PND group (67±60) %, (68±6) %, (69±5) % and (70±7)%, respectively, and the difference was statistically significant (t=3.369, 4.906, 3.787, 2.516, all P<0.05).The MoCA and MMSE scores of the PND group were (22.9±1.2) and (24.1±1.2) points, respectively, 1 day before surgery; and the MoCA and MMSE scores of the PND group were reduced to (20.8±1.2) and (21.3±0.7) points, respectively, 7 days after surgery, with statistically significant differences (t=3.523, 5.675, all P<0.05). MoCA and MMSE scores 7 days after surgery in the non-PND group were (22.4±1.3) and (23.1±1.6) points, respectively. Compared with the non-PND group, MoCA and MMSE scores 7 days after surgery in the PND group were reduced (t=2.630, 3.108, all P<0.05). The critical value of intraoperative SctO(2max)% was 13.74%, the area under the curve of PND was predicted to be 0.907 (95%CI: 0.819-0.995), sensitivity and specificity were 88.9% and 88.5%, respectively. Conclusion: SctO(2max)%>13.74% can be used as an indicator to predict PND occurrence in elderly patients with mild cognitive impairment during lumbar surgery.

Comparison of electrical characteristics between atrial and ventricular side His-bundle pacing in bradycardia patients

Background

His-bundle pacing (HBP) is recognized as the most physiological way of pacing but with less study focused on electrical characteristics in different site.

Purpose

We aimed to evaluate the differences of pacing and echocardiographic parameters between atrial and ventricular side His-bundle pacing.

Methods

Patients who successfully underwent HBP implantation from September 2018 to August 2019 were retrospectively analyzed. All patients were assigned to atrial-side HBP (aHBP) group or ventricular-side HBP (vHBP) group according to the location of the His-bundle pacing lead, which was confirmed by two methods including postoperative echocardiography and visualization of tricuspid valve annulus (TVA). The pacing and echocardiographic parameters were compared between two groups during the procedure and at 3-month follow-up.

Results

A total of 71 bradycardia patients who successfully underwent HBP implantation and confirmed lead position were included. Among them, twenty-seven were assigned to aHBP group and the other 44 were assigned to vHBP group with no significant differences in baseline clinical characteristics between two groups. During the procedure, the proportion of selective HBP was significantly higher (77.8% vs. 11.4%; P&lt;0.01) and the intra-procedural HV intervals was significantly longer (50.85±6.53 ms vs. 42.95±6.02 ms, P&lt;0.01) in aHBP group than in vHBP group. The capture threshold in vHBP group was significantly lower than in aHBP group at implantation (0.92±0.22 V/1.0ms vs. 1.05±0.26 V/1.0ms, P=0.03) and remain significantly difference after 3-month follow-up (0.98±0.23 V/1.0ms vs. 1.15±0.44 V/1.0ms, P=0.03). The R-wave amplitude was significantly higher in vHBP group than in aHBP group at implantation (5.82±2.52 mV vs. 3.74±1.81 mV, P&lt;0.01), and these differences still persisted during follow-up (5.88±2.51 mV vs. 3.67±1.61 mV, P&lt;0.01). During 3-month follow-up, an increase in the capture threshold &gt;1 V/1.0ms was seen in 2 cases in aHBP group while all patients remained stable in vHBP group. One patient developed a pocket hematoma in aHBP group compared to none in vHBP group. None of deterioration of tricuspid regurgitation and other procedure-related complications were observed during 3-month follow-up.

Conclusions

Ventricular side His-bundle pacing can achieve favourable pacing parameters including a lower pacing threshold and a higher R-wave amplitude than atrial side His-bundle pacing, which may be an ideal pacing strategy for patients in need of ventricular pacing.

Funding Acknowledgement

Type of funding source: None

Periodic repolarization dynamics for prediction of mortality: a systematic review and meta-analysis

Background

Prediction of death is the philosopher's stone of arrhythmology. The electrophysiology has proven to be an important tool to predict the risk of death. Periodic repolarization dynamics (PRD) is a novel electrocardiographic marker that indicates the sympathetic effect on repolarization. PRD qualifies the low-frequency oscillations of cardiac repolarization instability using high-resolution 12 channel 24-h Holter recording. Several studies showed that PRD was an independent predictor of all-cause mortality and cardiac mortality. However, the prediction value of PRD has not been established.

Purpose

To evaluate the prediction value of PRD as an approach of risk stratification that selects patients at a higher risk of death.

Methods

We conducted electronic searches of MEDLINE (PubMed), Embase, Cochrane Register of Controlled Trials (CENTRAL), Science Citation Index Expanded, WHO International Clinical Trials Registry platform (ICTRP) and ClinicalTrials.gov from inception to January 9th, 2020. We also screened for relevant abstracts from conferences including ACC Annual Scientific Sessions, ESC Congress and Annual Congress of the EHRA for the last five years (2014–2019). The primary outcome was all-cause mortality and secondary outcome was cardiac mortality. We included study with large sample size while more than one study were found based on the same originated population. We extracted data from included studies and reported pooled outcomes as hazard ratios (HRs) with 95% confidential intervals (CI) for time-to-event outcomes using DerSimonian-Laird random-effects model. We did statistical analyses using Stata version 12.0 and R version 3.6.1.

Results

5 studies including 6758 patients met all selection criteria for our meta-analysis. Follow-up period ranged from 20.4 to 75.1 months. Among 5 studies, 3 studies considered PRD as dichotomous variable and the cut-off value was 5.75 deg2, while 2 studies considered PRD as continuous variable and coefficient was expressed in standardized units (increase per standard deviation). We did subgroup analysis according to the type of variable because of heterogeneity. There was a significant higher risk of all-cause mortality in PRD ≥5.75 deg2 patients compared with PRD &lt;5.75 deg2 patients (HR 2.37, 95% CI 1.77–3.17). As for continuous variable, increased PRD was a predictor for all-cause death (HR 1.28, 95% CI 1.14–1.42) (Figure). The cardiac mortality was significantly increased in patients with PRD ≥5.75 deg2 vs PRD &lt;5.75 deg2 (HR 3.06, 95% CI 1.66–5.65). Increased PRD was associated with cardiac mortality in continuous variable subgroup (HR 1.34, 95% CI 1.21–1.48) (Figure).

Conclusion

Our findings suggest PRD is a significant predictor of all-cause mortality and cardiac mortality. PRD provides new additional electrophysiological indicator for risk stratification until further investigations are available.

Funding Acknowledgement

Type of funding source: None

A prognostic nomogram for event-free survival in patients with atrial fibrillation before cardiac resynchronization therapy

Background

Atrial fibrillation (AF), one of the most common comorbidities with heart failure (HF), is associated with worse prognosis in HF patients receiving cardiac resynchronization therapy (CRT). However, there is still no convenient tool to evaluate and identify patients with high risk of mortality and hospitalization due to heart failure in CRT candidates with AF.

Methods

We included 152 consecutive patients with AF for CRT in our hospital from January 2009 to July 2019. Multivariate Cox regression was applied to derive a nomogram, using multiple imputation for missing values and backward stepwise regression for variable selection.

Results

Five predictors were incorporated in the nomogram, including N-terminal pro brain natriuretic protein (NTproBNP) &gt;1745pg/mL, history of syncope, previous pulmonary hypertension (PHP), moderate or severe tricuspid regurgitation (TR), thyroid stimulating hormone (TSH) &gt;4mIU/L. Concordance index (0.70, 95% CI 0.62–0.77), corrected concordance index (0.67, 95% CI 0.59–0.74) and calibration curve showed optimal discrimination and calibration of the established nomogram. Significant difference of overall event-free survival was recognized by the nomogram-derived scores in patients with high risk (&gt;50 points), intermediate risk (21–50 points) and low risk (0–20 points) before CRT.

Conclusion

Our nomogram may be an applicable tool for early risk stratification among CRT candidates with AF.

Nomogram and risk stratification

Funding Acknowledgement

Type of funding source: None