High rate capability of S-doped ordered mesoporous carbon materials with directional arrangement of carbon layers and large d-spacing for sodium-ion battery

3D hierarchical self-supporting Bi2Se3-based anode for high-performance lithium/sodium-ion batteries

Bi2Se3 is a promising material for anodes in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) due to its abundance, easy preparation, and high capacity. However, its practical application is hindered by low conductivity and significant volume variation during cycling, leading to poor rate capability and cycling stability. Herein, a novel composite consisting of Bi2Se3 nanoplates deposited on carbon cloth (CC) and encapsulated by reduced graphene oxide (rGO) has been designed and synthesized. The composite structure combines the advantages of the Bi2Se3 nanoplates, CC substrate, and rGO encapsulation, leading to enhanced electrochemical properties. The physical vapor deposition of Bi2Se3 nanoplates onto CC ensures a high loading of active material, while the rGO encapsulation provides a conductive and stable framework for the composite. This synergistic design allows for improved electron and ion transport, as well as efficient accommodation of the volume changes during cycling. In LIBs, the composite demonstrates a high reversible capacity of 467.5 mAh/g at 0.1 A/g after 120 cycles. Moreover, it displays an outstanding rate capability, delivering a capacity of 398.6 mAh/g at 5.0 A/g. Similarly, in SIBs, the composite maintains a reversible capacity of 375.3 mAh/g at 0.1 A/g over 100 cycles and exhibits a high-rate capacity of 286.3 mAh/g at 5.0 A/g. This work represents a significant step forward in addressing the challenges associated with Bi2Se3 as an anode material, paving the way for the development of high-performance LIBs and SIBs.

Effects of crystal structure and electronic properties on lithium storage performance of artificial graphite

Graphite is nowadays commonly used as the main component of anode materials of lithium-ion batteries (LIBs). It is essential to deeply investigate the fundamentals of artificial graphite to obtain excellent anode, especially crystal structure and electronic properties. In this report, a series of graphite with different crystal structure were synthesized and used for anodes of LIBs. Meanwhile, a concise method is designed to evaluate qualitatively the conductivity of lithium ion (σLi) and a profound mechanism of lithium storage was revealed in terms of solid state theory. The conductivity analysis demonstrates that the graphite with longer crystal plane and lower stacking layers possesses higher conductivity of electron (σe). On the other hand, lower initial charge/discharge voltage indicates the graphite with lower La and higher Lc holds higher conductivity of lithium ion (σLi). According to the solid state theory, graphite is considered to be a semi-conductor with zero activation energy, while the lithium intercalated graphite is like a conductor. The conductivity of graphite mainly depends on the σe, while the conductivity of lithium intercalated graphite can be determined by the summation of σe and σLi. In lower charge/discharge rate, Li+ have enough time to insert into the graphitic layer, making the special capacity of graphite primarily determined by σe. However, with the increase of charge/discharge rate, Li+ insertion/extraction will become more difficult, making σLi become the mainly factor of the graphite special capacity. Therefore, the graphite with longer crystal plane and lower stacking layers owns higher specific capacity under slow charge/discharge rate, the graphite with shorter crystal plane and higher stacking layers shows relatively lower specific capacity under rapid charge/discharge rate. These results provide important insights into the design and improvement of graphite's electrochemical performance.

The Recent Progress of Pitch Nanoengineering to Obtain the Carbon Anode for High-Performance Sodium Ion Batteries

As an anode material for sodium ion batteries (SIBs), carbon materials have attracted people's interest because of their abundant resources, good structural stability and low cost. Among most carbon precursors, pitch is viewed as a promising one because of a higher carbon content, good oxidation reversibility and low cost. However, the pitch-based carbon obtained with direct pyrolysis of pitch displays a high degree of graphitization and small layer spacing, which is unfavorable for the storage of sodium ions. In recent years, with the aid of the development of the nanoengineering process, the storage of sodium ions with pitch-based carbon has been drastically improved. This review article summarizes the recent progress of pitch nanoengineering to obtain the carbon anode for high-performance SIBs, including porous structure adjustment, heteroatom doping, co-carbonization and pre-oxidation. In addition, the merits and demerits of a variety of nanoengineering processes are discussed, and future research directions of pitch-based carbon are prospected.

Surface-driven fast sodium storage enabled by Se-doped honeycomb-like macroporous carbon

Selenium (Se) is an ideal doping agent to modulate the structure of carbon materials to improve their sodium storage performance but has been rarely investigated. In the present study, a novel Se-doped honeycomb-like macroporous carbon (Se-HMC) is prepared by a surface crosslinking method using diphenyl diselenide as the carbon source and SiO₂ nanospheres as the template. Se-HMC has a high Se weight percentage above 10%, with a large surface area of 557 m² g^-1. Owing to the well-developed porous structure in combination with Se-assisted capacitive redox reactions, Se-HMC exhibits surface-dominated Na storage behaviors, thus presenting large capacity and fast Na storage capability. To be specific, Se-HMC delivers a high reversible capacity of 335 mA h g^-1 at 0.1 A g^-1, and after an 800-cycle repeated charge/discharge test at 1 A g^-1, the capacity is stable with no dramatic loss. Remarkably, the capacity remains 251 mA h g^-1 under a very large current density of 5 A g^-1 (≈20 C), demonstrating an ultrafast Na storage process. As far as we know, such a good rate performance has been rarely achieved for carbon anodes before.

Synthesis Strategies and Applications for Pitch-Based Anode: From Industrial By-Products to Power Sources

It is significant for saving energy to manufacture superb-property batteries. Carbon is one of the most competitive anode materials in batteries, but it is hard for commercial graphite anodes to meet the increasingly higher energy-storage requirements. Moreover, the price of other better-performing carbon materials (such as graphene) is much higher than graphite, which is not conducive to massive production. Pitch, the cheap by-product in the petroleum and coal industries, has high carbon content and yield, making it possible for commercialization. Developing pitch-based anodes can not only lower raw material costs but also realize the pitch's high value-added utilization. We comprehensively reviewed the latest synthesis strategies of pitch-derived materials and then introduced their application and research progress in lithium, sodium, and potassium ion batteries (LIBs, SIBs, and PIBs). Finally, we summarize and suggest the pitch's development trend for anodes and in other fields.

ZnFe2O4-Ni5P4 Mott-Schottky Heterojunctions to Promote Kinetics for Advanced Li-S Batteries

The practical progress of lithium-sulfur batteries is hindered by the serious shuttle effect and the slow oxidation-reduction kinetics of polysulfides. Herein, the ZnFe2O4-Ni5P4 Mott-Schottky heterojunction material is prepared to address these issues. Benefitting from a self-generated built-in electric field, ZnFe2O4-Ni5P4 as an efficient bidirectional catalysis regulates the charge distribution at the interface and accelerates electron transfer. Meanwhile, the synergy of the strong adsorption capacity derived from metal oxides and the outstanding catalytic performance that comes from metal phosphides strengthens the adsorption of polysulfides, reduces the energy barrier during the reaction, accelerates the conversion between sulfur species, and further accelerates the reaction kinetics. Hence, the cell with ZnFe2O4-Ni5P4/S harvests a high discharge capacity of 1132.4 mAh g-1 at 0.5C and displays a high Coulombic efficiency of 99.3% after 700 cycles. The ZnFe2O4-Ni5P4/S battery still maintains a capacity of 610.1 mAh g-1 with 84.4% capacity retention after 150 cycles at 0.1C under a high sulfur loading of 3.2 mg cm-2. This work provides a favorable reference and advanced guidance for developing Mott-Schottky heterojunctions in lithium-sulfur batteries.

Hydroxyapatite reinforced inorganic-organic hybrid nanocomposite as high-performance adsorbents for bilirubin removal in vitro and in pig models

Highly efficient removal of bilirubin from whole blood directly by hemoperfusion for liver failure therapy remains a challenge in the clinical field due to the low adsorption capacity, poor mechanical strength and low biocompatibility of adsorbents. In this work, a new class of nanocomposite adsorbents was constructed through an inorganic-organic co-crosslinked nanocomposite network between vinyltriethoxysilane (VTES)-functionalized hydroxyapatite nanoparticles (V-Hap) and non-ionic styrene-divinylbenzene (PS-DVB) resins (PS-DVB/V-Hap) using suspension polymerization. Notably, our adsorbent demonstrated substantially improved mechanical performance compared to the pure polymer, with the hardness and modulus increasing by nearly 3 and 2.5 times, respectively. Moreover, due to the development of a mesoporous structure, the prepared PS-DVB/V-Hap3 exhibited an ideal adsorption capacity of 40.27 mg g-1. More importantly, the obtained adsorbent beads showed outstanding blood compatibility and biocompatibility. Furthermore, in vivo extracorporeal hemoperfusion verified the efficacy and biosafety of the adsorbent for directly removing bilirubin from whole blood in pig models, and this material could potentially prevent liver damage and improve clinical outcomes. Taken together, the results suggest that PS-DVB/V-Hap3 beads can be used in commercial adsorption columns to threat hyperbilirubinemia patients through hemoperfusion, thus replacing the existing techniques where plasma separation is initially required.

Template synthesis of ordered mesoporous MgO with superior adsorption for Pb(II) and Cd(II)

Ordered mesoporous MgO was synthesized via template method by using magnesium nitrate as a precursor and amphiphilic triblock copolymer Pluronic F127 as a template. The products were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM), and the Brunauer-Emmett-Teller (BET) method was used to calculate the specific surface areas. The effects of aging time, relative humidity, and magnesium nitrate content on the morphology and textural properties of the products were studied. When the aging time was 36 h and the relative humidity was 40%, the ordered mesoporous MgO with uniform pore sizes (3.2 nm), high specific surface areas (517.2 m²/g), and high pore volumes (0.42 cm³/g) were obtained. Furthermore, the adsorption properties of ordered mesoporous MgO as adsorbent for removal of Pb(II) and Cd(II) ions were studied. The adsorption kinetics and isotherm data agreed well with pseudo-second-order model and Langmuir model, indicating that the adsorption of heavy metal ions on the ordered mesoporous MgO was mainly chemical and homogeneous adsorption. The maximum adsorption capacities for Pb(II) and Cd(II) ions were up to 3073.5 mg/g and 1485.1 mg/g, respectively.

Investigation of doping effects of different noble metals for ethanol gas sensors based on mesoporous In2O3

Elaborating the sensitization effects of different noble metals on In₂O₃has great significance in providing an optimum method to improve ethanol sensing performance. In this study, long-range ordered mesoporous In₂O₃has been fabricated through replicating the structure of SBA-15. Different noble metals (Au, Ag, Pt and Pd) with the same doping amount (1 at%) have been introduced by anin situdoping routine. The results of the gas sensing investigation indicate that the gas responses towards ethanol can be obviously increased by doping different noble metals. In particular, the best sensing performance towards ethanol detection can be achieved through Pd doping, and the sensors based on Pd-doped In₂O₃not only possess the highest response (39.0-100 ppm ethanol) but also have the shortest response and recovery times at the optimal operating temperature of 250 °C. The sensing mechanism of noble metal doped materials can be attributed to the synergetic effect combining 'catalysis' and 'electronic and chemical sensitization' of noble metals. In particular, the chemical state of the noble metal also has a great influence on the gas sensing mechanism. A detailed explanation of the enhancement of gas sensing performance through noble metal doping is presented in the gas sensing mechanism part of the manuscript.