Low-Temperature Resistant Stretchable Micro-Supercapacitor Based on 3D Printed Octet-Truss Design

Recently, stretchable micro-supercapacitors (MSCs) that can be easily integrated into electronic devices have attracted research and industrial attentions. In this work, three-dimensional (3D) stretchable MSCs with an octet-truss electrode (OTE) design have been demonstrated by a rapid digital light processing (DLP) process. The 3D-printed electrode structure is beneficial for electrode-electrolyte interface formation and consequently increases the number of ions adsorbed on the electrode surface. The designed MSCs can achieve a high capacitance as ≈74.76 mF cm^-3 under 1 mA cm^-3 at room temperature even under a high mechanical deformation, and can achieve 19.53 mF cm^-3 under 0.1 mA cm^-3 at a low temperature (-30 °C). Moreover, finite element analysis (FEA) reveals the OTE structure provides 8 times more contact area per unit volume at the electrode-electrolyte interface compared to the traditional interdigital electrode (IDE). This work combines structural design and 3D printing techniques, which provides new insights into highly stretchable MSCs for next-generation electronic devices.

Low-Coordinated Zn-N2 Sites as Bidirectional Atomic Catalysis for Room-Temperature Na-S Batteries

The rational design of advanced catalysts for sodium-sulfur (Na-S) batteries is important but remains challenging due to the limited understanding of sulfur catalytic mechanisms. Here, we propose an efficient sulfur host consisting of atomic low-coordinated Zn-N₂ sites dispersed on N-rich microporous graphene (Zn-N₂@NG), which realizes state-of-the-art sodium-storage performance with a high sulfur content of 66 wt %, high-rate capability (467 mA h g^-1 at 5 A g^-1), and long cycling stability for 6500 cycles with an ultralow capacity decay rate of 0.0062% per cycle. Ex situ methods combined with theoretical calculations demonstrate the superior bidirectional catalysis of Zn-N₂ sites on sulfur conversion (S₈ ↔ Na₂S). Furthermore, in situ transmission electron microscopy was applied to visualize the microscopic S redox evolution under the catalysis of Zn-N₂ sites without liquid electrolytes. During the sodiation process, both surface S nanoparticles and S molecules in the mircopores of Zn-N₂@NG quickly convert into Na₂S nanograins. During the following desodiation process, only a small part of the above Na₂S can be oxidized into Na₂S_x. These results reveal that, without liquid electrolytes, Na₂S is difficult to be decomposed even with the assistance of Zn-N₂ sites. This conclusion emphasizes the critical role of liquid electrolytes in the catalytic oxidation of Na₂S, which was usually ignored by previous works.

Role of magnetic substances in adsorption removal of ciprofloxacin by gamma ferric oxide and ferrites co-modified carbon nanotubes

Antibiotics have been considered an evolving environmental challenge in the last few decades due to their mutagenic and persistent effects. Herein, we synthesized γ-Fe₂O₃ and ferrites nanocomposites co-modified carbon nanotubes (γ-Fe₂O₃/MFe₂O₄/CNTs, M: Co, Cu, and Mn) with high crystallinity, thermostability, and magnetization for the adsorption removal of ciprofloxacin. The experimental equilibrium adsorption capacities of ciprofloxacin on γ-Fe₂O₃/MFe₂O₄/CNTs were 44.54 (Co), 41.13 (Cu), and 41.53 (Mn) mg/g, respectively. The adsorption behaviors followed the Langmuir isotherm and pseudo-first-order models. Density functional theory calculations revealed that the active sites preferentially appeared on the oxygen of the carboxyl group in ciprofloxacin, and the calculated adsorption energies of ciprofloxacin on CNTs, γ-Fe₂O₃, CoFe₂O₄, CuFe₂O₄, and MnFe₂O₄ were -4.82, -1.08, -2.49, -0.60, and 5.69 eV, respectively. The addition of γ-Fe₂O₃ changed the adsorption mechanism of ciprofloxacin on MFe₂O₄/CNTs and γ-Fe₂O₃/MFe₂O₄/CNTs. CNTs and CoFe₂O₄ controlled the cobalt system of γ-Fe₂O₃/CoFe₂O₄/CNTs, while CNTs and γ-Fe₂O₃ ruled the adsorption interaction and capacity of copper and manganese systems. This work reveals the role of magnetic substances, which is beneficial to the preparation and environmental application of similar adsorbents.

Mechanisms of interfacial catalysis and mass transfer in a flow-through electro-peroxone process

To investigate the catalytic mechanism and mass transfer efficiency in the removal of amitriptyline using an electro-peroxide process, a CuFe₂O₄-modified carbon cloth cathode was prepared and utilized in a reaction unit. The results demonstrated a remarkable efficacy of the system, achieving 91.0% amitriptyline removal, 68.3% mineralization, 41.2% mineralization current efficiency, and 0.24 kWh/m³ energy consumption within just five minutes of treatment. The study revealed that the exposed Fe atoms of the ferrite nanoparticles, with a size of 22.7 nm and 89.7% crystallinity, functioned as mediators to bind the adsorbed O atoms. The 3d_xy, 3d_xz, and 3d²_z orbitals of Fe atoms interacted with the 2p_z orbital of O atoms of H₂O₂ and O₃ to form σ and π bonds, facilitating the adsorption-activation of H₂O₂ and O₃ into hydroxyl radicals. These hydroxyl radicals (∼ 1.15 × 10¹³ mol/L) were distributed at the cathode-solution interface and rapidly consumed along the direction of liquid flow. The flow-through cathode design improved the mass transfer of aqueous O₃ and in-situ generated H₂O₂, leading to an increased yield of hydroxyl radicals, as well as the contact time and space between hydroxyl radicals and amitriptyline. Ultimately, this resulted in a higher degradation efficiency of the system.

Metal-Organic-Framework-Derived 3D Hierarchical Matrixes for High-Performance Flexible Li-S Batteries

Lithium-sulfur (Li-S) batteries have shown exceptional theoretical energy densities, making them a promising candidate for next-generation energy storage systems. However, their practical application is limited by several challenging issues, such as uncontrollable Li dendrite growth, sluggish electrochemical kinetics, and the shuttling effect of lithium polysulfides (LiPSs). To overcome these issues, we designed and synthesized hierarchical matrixes on carbon cloth (CC) by using metal-organic frameworks (MOFs). ZnO nanosheet arrays were used as anode hosts (CC-ZnO) to enable stable Li plating and stripping. The symmetric cell with CC-ZnO@Li was demonstrated to have enhanced cycling stability, with a voltage hysteresis of ∼25 mV for over 800 h at 1 mA cm^-2 and 1 mAh cm^-2. To address the cathode challenges, we developed a multifunctional CC-NC-Co cathode host with physical confinement, chemical anchoring, and excellent electrocatalysis. The full cells with CC-ZnO@Li anodes and CC-NC-Co@S cathodes exhibited excellent electrochemical performance, with long cycling life (0.02% and 0.03% capacity decay per cycle when cycling 900 times at 0.5 C and 600 times at 1 C, respectively) and outstanding rate performance (793 mAh g^-1 at 4 C). Additionally, the pouch cell based on the flexible CC-ZnO@Li anode and CC-NC-Co@S cathode showed good stability in different bending states. Overall, our study presents an effective strategy for preparing flexible Li and S hosts with hierarchical structures derived from MOF, which can pave the way for high-performance Li-S batteries.

Understanding the Highly Reversible Potassium Storage of Hollow Ternary (Bi-Sb)2S3@N-C Nanocube

Metal sulfide anodes have aroused much attention in potassium ion batteries (PIBs) owing to their high theoretical capacities, but the sluggish kinetics and inferior cycling performance caused by severe volumetric change and particle pulverization greatly hinder their further development. Herein, robust hollow structure design together with phase structure engineering endow (Bi-Sb)₂S₃@N-C anode with superior (de)potassiation kinetics and excellent electrochemical performances in PIBs. Specifically, in situ X-ray diffraction combined with density functional theory calculations and ex situ X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy (TEM) analyses indicated a fresh reaction mechanism of (Bi-Sb)₂S₃ anode with a distinctive multistep (de)potassiation route along (003) plane of (Bi,Sb) alloy thanks to the Bi-Sb phase regulation in (Bi-Sb)₂S₃ anode, ensuring it with superior reaction kinetics. Moreover, in situ TEM characterization revealed the advantages of the hollow nanostructure with carbon shell, facilitating fast ion transport kinetics and high tolerance of volume change as well as enabling the structural integrity of electrode material during (de)potassiation. As a result, the (Bi-Sb)₂S₃ hollow nanocube with N-doped carbon shell ((Bi-Sb)₂S₃@N-C) delivers a high initial Coulombic efficiency of 66.3%, a great rate performance of 289 mAh g^-1 at 2.0 A g^-1, and an ultralong cycling life (89% retention after 220 cycles at 0.1 A g^-1 and 85% retention after 1600 cycles at 2.0 A g^-1) in PIBs. Furthermore, the full cell of (Bi-Sb)₂S₃@N-C//PTCDA affords a high reversible capacity of 281 mA h g^-1 at 1.0 A g^-1 after 300 cycles. This work combines structural design and in situ techniques, proving a successful nanostructure engineering strategy to rationalize alloy-type electrode materials for PIBs.

Cobalt-nickel bimetallic sulfide (NiS2/CoS2) based dual-carbon framework for super sodium ion storage

Design hybrid metal sulfides-based anode materials is one of the most effective approaches to improve the performance of sodium-ion batteries (SIBs). However, owing to the huge volume expansion, the capacity of sulfide-based anode will decay significantly after repeated charge/discharge processes. Herein, we reported the successful demonstration of anode material based on concaved NiS₂@CoS₂ nanocube (NCSC) via a chemical etching strategy, which was derived from etching and sulfidation of Ni-Co coordination polymers (NiCoCP) precursor. The obtained NCSC anode materials deliver a high specific sodium storage capacity of 848 mAh g^-1 at 0.1 A g^-1 and a stable cyclability of 572 mAh g^-1 at 5 A g^-1 after 830 cycles. This special etching strategy exploit a novel way for the design and preparation of high-performance anode materials for SIBs.

Multimaterial Three-Dimensional Printing of Ultraviolet-Curable Ionic Conductive Elastomers with Diverse Polymers for Multifunctional Flexible Electronics

Ionic conductive elastomers (ICEs) are emerging stretchable and ionic conductive materials that are solvent-free and thus demonstrate excellent thermal stability. Three-dimensional (3D) printing that creates complex 3D structures in free forms is considered as an ideal approach to manufacture sophisticated ICE-based devices. However, the current technologies constrain 3D printed ICE structures in a single material, which greatly limits functionality and performance of ICE-based devices and machines. Here, we report a digital light processing (DLP)-based multimaterial 3D printing capability to seemly integrate ultraviolet-curable ICE (UV-ICE) with nonconductive materials to create ionic flexible electronic devices in 3D forms with enhanced performance. This unique capability allows us to readily manufacture various 3D flexible electronic devices. To demonstrate this, we printed UV-ICE circuits into polymer substrates with different mechanical properties to create resistive strain and force sensors; we printed flexible capacitive sensors with high sensitivity (2 kPa^-1) and a wide range of measured pressures (from 5 Pa to 550 kPa) by creating a complex microstructure in the dielectric layer; we even realized ionic conductor-activated four-dimensional (4D) printing by printing a UV-ICE circuit into a shape memory polymer substrate. The proposed approach paves a new efficient way to realize multifunctional flexible devices and machines by bonding ICEs with other polymers in 3D forms.

[Epidemiological investigation on the local epidemic situation in Zhengzhou High-Tech Zone caused by SARS-CoV-2 Delta variant]

This study collected epidemic data of COVID-19 in Zhengzhou from January 1 to January 20 in 2022. The epidemiological characteristics of the local epidemic in Zhengzhou High-tech Zone caused by the SARS-CoV-2 Delta variant were analyzed through epidemiological survey and big data analysis, which could provide a scientific basis for the prevention and control of the Delta variant. In detail, a total of 276 close contacts and 599 secondary close contacts were found in this study. The attack rate of close contacts and secondary close contacts was 5.43% (15/276) and 0.17% (1/599), respectively. There were 10 confirmed cases associated with the chain of transmission. Among them, the attack rates in close contacts of the first, second, third, fourth and fifth generation cases were 20.00% (5/25), 17.86% (5/28), 0.72% (1/139) and 14.81% (4/27), 0 (0/57), respectively. The attack rates in close contacts after sharing rooms/beds, having meals, having neighbor contacts, sharing vehicles with the patients, having same space contacts, and having work contacts were 26.67%, 9.10%, 8.33%, 4.55%, 1.43%, and 0 respectively. Collectively, the local epidemic situation in Zhengzhou High-tech Zone has an obvious family cluster. Prevention and control work should focus on decreasing family clusters of cases and community transmission.

Surface characteristics of polystyrene microplastics mainly determine their coagulation performances

In this study, polyaluminum sulfate (PAS) coagulant was selected to evaluate the coagulation performance of polystyrene microplastics. Overall, polystyrene removal efficiency was 90.4 % at the optimal dosage of 7.5 g/L of PAS. In addition to the type of coagulants (e.g. polyaluminum chloride, iron(III) chloride, and polyferric sulfate), surface characteristics such as densities, particle sizes, morphologies, adsorbed substances, and functional groups can also significantly impact the coagulation performance. The coagulation ratios are reduced to (2.6 ± 0.1)% when the densities of microplastics decrease. Aging treatments involving NaOH, H₂SO₄, NaClO, CH₃OH, and O₃ promoted coagulation, whereas UV and Na₂S₂O₃ treatments inhibited (64.1 ± 9.7)% and (79.3 ± 8.0)% of polystyrene removals, respectively. In contrast, Fe(NO₃)₃ treatment did not affect the removal ratio. Further characterization of polystyrene before and after coagulation exemplified that the functional groups (CO, CO, and CH) and the rough surfaces of PAS provided adsorption and interception sites for hydrolysis products of the PAS.

Spherical Templating of CoSe2 Nanoparticle-Decorated MXenes for Lithium-Sulfur Batteries

Two-dimensional MXenes produce competitive performances when incorporated into lithium-sulfur batteries (LSBs), solving key problems such as the poor electronic conductivity of sulfur and dissolution of its polysulfide intermediates. However, MXene nanosheets are known to easily aggregate and restack during electrode fabrication, filtration, or water removal, limiting their practical applicability. Furthermore, in complex electrocatalytic reactions like the multistep sulfur reduction process in LSBs, MXene alone is insufficient to ensure an optimal reaction pathway. In this work, we demonstrate for the first time a loose templating of sulfur spheres using Ti₃C₂T_x MXene nanosheets decorated with polymorphic CoSe₂ nanoparticles. This work shows that the templating of sulfur spheres using nanoparticle-decorated MXene nanosheets can prevent nanosheet aggregation and exert a strong electrocatalytic effect, thereby enabling improved reaction kinetics and battery performance. The S@MXene-CoSe₂ cathode demonstrated a long cycle life of 1000 cycles and a low capacity decay rate of 0.06% per cycle in LSBs.

A Flexible Vertical-Section Wood/MXene Electrode with Excellent Performance Fabricated by Building a Highly Accessible Bonding Interface

Cross-section wood (CW) is generally used as a host for free-standing electrodes, as the abundant opened pores can provide large space for loading guest materials with high electrical conductivity and electrochemical activity. However, there is still a challenge for CW to be used in flexible supercapacitors (SCs) because of its low mechanical strength. Herein, as an alternative to CW, vertical-section wood (VW) with excellent mechanical strength and good flexibility is developed and used as a free-standing and flexible electrode by using Ti₃C₂T_x (MXene) with ultrahigh conductivity and good electrochemical activity as a guest material. In particular, the highly accessible bonding interface for Ti₃C₂T_x is first built by delignification on VW to generate abundant pores for continuously absorbing Ti₃C₂T_x and to expose cellulose with abundant oxygen-containing groups for stable combination with Ti₃C₂T_x. Then, cyclic pressing is used to form negative pressure to pump the Ti₃C₂T_x suspension into VW, combining with a preheating process to trigger layer-by-layer self-assembly of Ti₃C₂T_x nanosheets onto a wood cell wall by evaporating water in the suspension. As a result, the free-standing electrode has a large Ti₃C₂T_x loading mass proportion of 33 wt %, a high conductivity of 3.14 S cm^-1, and good flexibility with much higher mechanical strength of 15.1 MPa than 0.4 MPa of CW. The symmetric SC delivers a good specific capacitance of 805 mF cm^-2 at 0.5 mA cm^-2, a remarkably high rate capability of 84% to 10 mA cm^-2, and an energy density of 13.85 μW h cm^-2 at 87.5 μW cm^-2. Additionally, this SC shows a long lifespan of 90.5% after 10,000th charge and discharge cycles even at a constant bending angle of 90°, suggesting promising potential in flexible devices.

Double-Enhanced Core-Shell-Shell Sb2S3/Sb@TiO2@C Nanorod Composites for Lithium- and Sodium-Ion Batteries

For most alloying- and conversion-type anode materials, a huge volume expansion and structure degradation of the electrodes always hinder their applications. In this work, a novel core-shell-shell Sb2S3/Sb@TiO2@C nanorod composite has been designed layer by layer, which includes an inner Sb2S3/Sb heterostructure core protected by an oxygen-deficient TiO2 shell and a conductive carbon shell. It is interesting to observe that, during the carbothermic reduction process, the previous Sb2S3 nanorod cores are partially reduced into a metallic Sb phase and the reduced TiO2 also creates many oxygen vacancies, which can greatly enhance the conductivity of the semiconductor Sb2S3. Thanks to the double effects of the TiO2 middle shell and carbon outer shell, the unique double-shelled structure design creates an enhanced dual protection, which can better accommodate the volume-expansive deformation and preserve the structural integrity of the active Sb2S3/Sb core. Especially, the TiO2 middle layer is self-assembled by numerous nanoparticles acting as a nanopillar backbone, which supports between the nanorod core and outer carbon shell to better buffer the volume changes. As a result, the core-shell-shell Sb2S3/Sb@TiO2@C anode shows lithium and sodium storage performances superior to those of the pristine Sb2S3 and core-shell Sb2S3@TiO2 electrodes. For lithium-ion batteries, the Sb2S3/Sb@TiO2@C nanorod composite achieves an initial discharge/recharge capacity of 1244.9/1005.1 mAh g-1 with an initial Coulombic efficiency of about 80.7%, an enhanced rate capability with a capacity of 593.2 mA h g-1 at 5.0 A g-1, and prolonged cycling life for 500 cycles with a reversible capacity of 495.8 mAh g-1 at 0.5 A g-1. For sodium-ion batteries, the nanorodalso exhibits an improved performance with an initial discharge/recharge capacity of 781.4/574.0 mAh g-1 (initial Coulombic efficiency of about 73.46%) and cycling for 400 cycles with a reversible capacity of 422.6 mAh g-1 at 0.8 A g-1. This research sheds light upon double-shell structure designs with an effective middle shell to enhance the energy storage performance of electrode materials.

3D-Printed Sodiophilic V2CTx/rGO-CNT MXene Microgrid Aerogel for Stable Na Metal Anode with High Areal Capacity

Featuring a high theoretical capacity, low cost, and abundant resources, sodium metal has emerged as an ideal anode material for sodium ion batteries. However, the real feasibility of sodium metal anodes is still hampered by the uncontrolled sodium dendrite problems. Herein, an artificial three-dimensional (3D) hierarchical porous sodiophilic V₂CT_x/rGO-CNT microgrid aerogel is fabricated by a direct-ink writing 3D printing technology and further adopted as the matrix of Na metal to deliver a Na@V₂CT_x/rGO-CNT sodium metal anode. Upon cycling, the V₂CT_x/rGO-CNT electrode can yield a superior cycling life of more than 3000 h (2 mA cm^-2, 10 mAh cm^-2) with an average Coulombic efficiency of 99.54%. More attractively, it can even sustain a stable operation over 900 h at 5 mA cm^-2 with an ultrahigh areal capacity of 50 mAh cm^-2. In situ and ex situ characterizations and density functional theory simulation analyses prove that V₂CT_x with abundant sodiophilic functional groups can effectively guide the sodium metal nucleation and uniform deposition, thus enabling a dendrite-free morphology. Moreover, a full cell pairing a Na@V₂CT_x/rGO-CNT anode with a Na₃V₂(PO₄)₃@C-rGO cathode can deliver a high reversible capacity of 86.27 mAh g^-1 after 400 cycles at 100 mA g^-1. This work not only clarifies the superior Na deposition chemistry on the sodiophilic V₂CT_x/rGO-CNT microgrid aerogel electrode but also offers an approach for fabricating advanced Na metal anodes via a 3D printing method.

[Perioperative management and complication control of Le Fort Ⅲ osteotomy in children with syndromic craniosynostosis]

Objective: To summarize the preliminary efficacy, perioperative management and complications of Le Fort Ⅲ osteotomy and midface distraction in patients with syndromic craniosynostosis by retrospective analysis, and to provide clinical experience for reference. Methods: From October 2017 to January 2020, 20 patients with syndromic craniosynostosis underwent Le Fort Ⅲ osteotomy and distraction in The Department of Oral and Maxillofacial Surgery of Peking University International Hospital, including 11 males and 9 females, were involved. The median age was 7 years (1.5 to 15 years). Preoperative risk prevention plan was put forward by multidisciplinary evaluation, and preoperative intervention was carried out. The diagnostic data of SNA, airway volume, polysomnography (PSG), ophthalmology and occlusal relationship were obtained through specialized examination, and osteotomy and distraction surgical plan was formulated through virtual surgical planning. CT was taken 1 week and 3, 6, 12 months after operation, PSG and eye protrudence examination were conducted to evaluate the therapeutic effect, syndrome type, multiple disciplinary treatment (MDT) intervention, occurrence and outcome of complications were summarized. Results: There were 15 cases of Crouzon syndrome and 5 cases of Pfeiffer syndrome. Sleep apnea was the first complaint in 18 cases and exophthalmia in 2 cases. Preoperative interventional therapy included 4 cases of adenoid surgery, 2 cases of continuous positive airway pressure and 2 cases of maxillary expansion. The most common surgical complications were accidental fracture (14/20 cases, 70%), cerebrospinal fluid fistula (2 cases), internal carotid cavernous sinus fistula (1 case), postoperative hyponatraemia (5 cases), crying syndrome (2 cases), wound infection (2 cases), trichiasis of lower eyelid (4 cases), and nasal malformation (1 case). Three cases underwent unplanned secondary surgery. SNA, airway volume and mean percutaneous arterial oxygen saturation (SpO₂) six months after operation were significantly higher than those before operation (F=10.09, P=0.001; F=5.13, P<0.001; F=10.78, P=0.001), and the protrusion and apnea hypopnea index were significantly lower than those before surgery (F=6.73, P=0.010; F=18.47, P<0.001). There were no significant differences in SNA, airway volume, mean SpO₂, ophthalmology between 6 months after surgery and 1 year after surgery (P>0.05). Conclusions: Perioperative safety assessment and early intervention of MDT is an effective diagnosis and treatment model of Le Fort Ⅲ osteotomy and distraction for syndromic craniosynosis. The operative complications are mainly local, and systemic complications are controllable.

Topotactic Epitaxy Self-Assembly of Potassium Manganese Hexacyanoferrate Superstructures for Highly Reversible Sodium-Ion Batteries

The cycle stability and voltage retention of a Na₂Mn[Fe(CN)₆] (NMF) cathode for sodium-ion batteries (SIBs) has been impeded by the huge distortion from NaMn^II[Fe^III(CN)₆] to Mn^III[Fe^III(CN)₆] caused by the Jahn-Teller (JT) effect of Mn³⁺. Herein, we propose a topotactic epitaxy process to generate K₂Mn[Fe(CN)₆] (KMF) submicron octahedra and assemble them into octahedral superstructures (OSs) by tuning the kinetics of topotactic transformation. As the SIB cathode, the self-assembly behavior of KMF improves the structural stability and decreases the contact area with the electrolyte, thereby inhibiting the transition metal in the KMF cathode from dissolving in the electrolyte. More importantly, the KMF partly transforms into NMF with Na⁺ de/intercalation, and the existing KMF acts as a stabilizer to disrupt the long-range JT order of NMF, thereby suppressing the overall JT distortion. As a result, the electrochemical performances of KMF cathodes outperform NMF with a highly reversible phase transition and outstanding cycling performance, and 80% capacity retention after 1500/1300 cycles at 0.1/0.5 A g^-1. This work not only promotes creative synthetic methodologies but also promotes to explore the relationship between Jahn-Teller structural deformation and cycle stability.

Ladder Mechanisms of Ion Transport in Prussian Blue Analogues

Prussian blue (PB) and its analogues (PBAs) are drawing attention as promising materials for sodium-ion batteries and other applications, such as desalination of water. Because of the possibilities to explore many analogous materials with engineered, defect-rich environments, computational optimization of ion-transport mechanisms that are key to the device performance could facilitate real-world applications. In this work, we have applied a multiscale approach involving quantum chemistry, self-consistent mean-field theory, and finite-element modeling to investigate ion transport in PBAs. We identify a cyanide-mediated ladder mechanism as the primary process of ion transport. Defects are found to be impermissible to diffusion, and a random distribution model accurately predicts the impact of defect concentrations. Notably, the inclusion of intermediary local minima in the models is key for predicting a realistic diffusion constant. Furthermore, the intermediary landscape is found to be an essential difference between both the intercalating species and the type of cation doping in PBAs. We also show that the ladder mechanism, when employed in multiscale computations, properly predicts the macroscopic charging performance based on atomistic results. In conclusion, the findings in this work may suggest the guiding principles for the design of new and effective PBAs for different applications.

A minireview on chemical vapor deposition growth of wafer-scale monolayer h-BN single crystals

Hexagonal boron nitride (h-BN), with its excellent stability, flat surface, and large bandgap, plays a role in a variety of fundamental science and technology fields. The past few years have witnessed significant development in the scaled growth of h-BN single crystals. Currently, the size of h-BN crystal can be reached up to wafer-scale, paving the way towards industrial production and commercial applications. In this minireview, recent academic breakthroughs regarding the controlled growth of large-sized h-BN single crystals via chemical vapor deposition (CVD) are presented. The as-developed technique in terms of growth parameters, choice of catalysts, and the mechanism is fully emphasized, offering a guideline in enhancing the size and quality of h-BN. Several typical metal catalysts have been used in shaping scaled h-BN single crystals, of which the metal Cu substrate has drawn the most intensive attention. The significant advances in expanding the size of h-BN single crystals will largely push forward the way to h-BN industrialization and commercialization. The past few years have witnessed significant development in the scaled growth of h-BN single crystals. Currently, the size of h-BN crystal can be reached up to wafer-scale, paving the way towards industrial production and commercial applications. In this minireview, recent academic breakthroughs regarding controlled growth of large-sized h-BN single crystals via chemical vapor deposition (CVD) are present. The as-developed technique in terms of growth parameters, choice of catalysts and mechanism is fully emphasized, offering a guideline in enhancing size and quality of h-BN. Several typical metal catalysts are exhibited in shaping scaled h-BN single crystals, of which the metal Cu substrate has drawn the most intensive attentions.

Defect-Engineered 3D hierarchical NiMo3S4 nanoflowers as bifunctional electrocatalyst for overall water splitting

The design and construction of bifunctional electrocatalysts with high activity and durability is essential for overall water splitting. Herein, a unique 3D hierarchical NiMo₃S₄ nanoflowers with abundant defects and reactive sites were grown directly on carbon textiles (NiMo₃S₄/CTs) using a facile hydrothermal synthesis method. The defect-rich NiMo₃S₄ nanoflakes, prepared by doping Ni²⁺ in the lattice of Mo-S, displays extended d-spacing of (002) crystal plane, resulting in the electrocatalytic activity of hydrogen evolution and oxygen evolution reaction (HER and OER) was improved under alkaline conditions. The self-supported NiMo₃S₄/CTs electrode delivers a small overpotential of 149.5 mV for HER and 126.2 mV for OER at 10 mA cm^-2, respectively. Based on detailed structure analysis and density functional theory (DFT) calculations, the excellent HER and OER activities can be attributed to the unique structure of the nanoflowers, where the metallic characteristics for Ni-doped Mo-S lead to the enhancement of intrinsic conductivity and the rich abundance of Ni³⁺ active sites. As a result, the NiMo₃S₄/CTs as efficient bifunctional electrocatalysts for overall water-splitting was performed in alkaline electrolyte, where the system required only 1.55, 1.66 and 1.76 V to deliver current densities of 10, 50 and 100 mA cm^-2, respectively. This study provides a new method for improving the electrocatalysis properties of transition metal sulfides by metal-ion doping to generate more active defect sites, thus promoting the development of non-noble-metal electrocatalysts for overall water splitting.

ZnSe Modified Zinc Metal Anodes: Toward Enhanced Zincophilicity and Ionic Diffusion

Zinc metal is an ideal candidate for aqueous rechargeable batteries due to its high theoretical capacity and natural abundance. However, its commercialization is inevitably challenged by several critical factors such as dendrite growth and parasitic side-reactions, leading to low coulombic efficiency and a limited lifespan. Herein, a modified Zn foil with a zincophilic ZnSe layer deposited by a simple selenization process is proposed. An order of magnitude stronger adsorption capability toward Zn²⁺ ions and uniform ion diffusion tunnels of ZnSe enables lower nucleation energy barrier and faster ion-diffusion kinetics. Meanwhile, detrimental Zn corrosion in aqueous system is also effectively mitigated. As a result, ZnSe@Zn anode shows reversible Zn plating/stripping (1700 h at 1 mA cm^-2 ) with ultra-low voltage hysteresis (41 mV), contributing to exceptional cycling stability over 500 cycles with negligible capacity fading for the ZnSe@Zn/MnO₂ full cell.