Explore the vast range of titles available.

Tin selenide (SnSe2) is considered a promising anode of the lithium‐ion battery because of its tunable interlayer space, abundant active sites, and high theoretical capacity. However, the low electronic conductivity and large volume variation during the charging/discharging processes inevitably result in inadequate specific capacity and inferior cyclic stability. Herein, a high‐throughput wet chemical method to synthesize SnSe2/SnSe heterostructures is designed and used as anodes of lithium‐ion batteries. The hierarchical nanoflower morphology of such heterostructures buffers the volume expansion, while the built‐in electric field and metallic feature increase the charge transport capability. As expected, the superb specific capacity (≈911.4 mAh g−1 at 0.1 A g−1), high‐rate performance, and outstanding cyclic stability are obtained in the lithium‐ion batteries composed of SnSe2/SnSe anodes. More intriguingly, a reversible specific capacity (≈374.7 mAh g−1 at 2.5 A g−1) is maintained after 1000 cycles. The internal lithium storage mechanism is clarified by density functional theory (DFT) calculations and in situ characterizations. This work hereby provides a new paradigm for enhancing lithium‐ion battery performances by constructing heterostructures. A facile and high‐throughput wet chemical strategy for the batch synthesis of SnSe2/SnSe heterostructures is developed and used as anodes of lithium‐ion batteries. In view of the unique hierarchical nanoflower morphology, built‐in electric field, and metallic feature in such heterostructures, excellent specific capacity, high rate performance, and outstanding cyclic stability are achieved in the lithium‐ion battery.

As a biomass waste, hemp stems have the advantages of low cost and abundance, and it is regarded as a promising anode material with a high specific capacity. In this paper, activated carbon derived from hemp stems is prepared by low-temperature carbonization and high-temperature activation. The results of characterizations show the activated carbon has more pores due to the advantages of natural porous structure of hemp stem. The aperture size is mainly microporous, and there are mesopores and macropores in the porous carbon. The porous carbon has an excellent reversible capacity of 495 mAh/g after 100 cycles at 0.2 °C as the anode of lithium-ion battery. Compared with the graphite electrode, the electrochemical property of activated carbon is significantly improved due to the reasonable distribution of pore size. The preparation of the activated carbon provides a new idea for low cost and rapid preparation of anode materials for high capacity lithium-ion batteries.

The low specific capacity and sluggish electrochemical reaction kinetics greatly block the development of sodium-ion batteries (SIBs). New high-performance electrode materials will enhance development and are urgently required for SIBs. Herein, we report the preparation of supersaturated bridge-sulfur and vanadium co-doped MoS 2 nanosheet arrays on carbon cloth (denoted as V-MoS 2+x /CC). The bridge-sulfur in MoS 2 has been created as a new active site for greater Na + storage. The vanadium doping increases the density of carriers and facilitates accelerated electron transfer. The synergistic dual-doping effects endow the V-MoS 2+x /CC anodes with high sodium storage performance. The optimized V-MoS 2.49 /CC gives superhigh capacities of 370 and 214 mAh·g −1 at 0.1 and 10 A·g −1 within 0.4−3.0 V, respectively. After cycling 3,000 times at 2 A·g −1 , almost 83% of the reversible capacity is maintained. The findings indicate that the electrochemical performances of metal sulfides can be further improved by edge-engineering and lattice-doping co-modification concept.

To suppress the volume expansion and thus improve the performance of antimonene as a promising anode for lithium-ion batteries, we have systematically studied the stability, structural and electronic properties of the antimonene capped with graphene (G/Sb heterostructure) upon the intercalation and diffusion of Li atoms by first-principles calculations based on van der Waals (vdW) corrected density functional theory. G/Sb exhibits higher Young’s modulus (armchair: 145.20, zigzag: 144.36 N m−1) and improved electrical conductivity (bandgap of 0.03 eV) compared with those of antimonene. Li favors incorporating into the interlayer region of G/Sb rather than the outside surfaces of graphene and antimonene of G/Sb heterostructure, which is caused by the synergistic effect. The in-plane lattice constants of G/Sb heterostructure expand only around 4.5%, and the interlayer distance of G/Sb increases slightly (0.22 Å) at the case of fully lithiation, which indicates that the capping of graphene on antimonene can effectively suppress the volumetric expansion during the charging process. Additionally, the hybrid G/Sb heterostructure has little influence on the migration behaviors of Li on the outside of graphene and Sb surfaces compared with their free-standing monolayers. However, the migration energy barrier for Li diffusion in the interlayer region (about 0.59 eV) is significantly affected by the geometry structure, which can be reduced to 0.34 eV simply by increasing the interlayer distance. The higher theoretical specific capacity (369.03 mAh g−1 vs 208 mAh g−1 for antimonene monolayer) and suitable open circuit voltage (from 0.11 V to 0.89 V) of G/Sb heterostructure are beneficial for anode materials of lithium-ion batteries. The above results reveal that G/Sb heterostructure may be an ideal candidate of anode for high recycling–rate and portable lithium-ion batteries.

The slow redox kinetics of polysulfides and the difficulties in decomposition of Li 2 S during the charge and discharge processes are two serious obstacles to the practical application of lithium-sulfur batteries. Herein, we construct the Fe-Co diatomic catalytic materials supported by hollow carbon spheres to achieve high-efficiency catalysis for the conversion of polysulfides and the decomposition of Li 2 S simultaneously. The Fe atom center is beneficial to accelerate the discharge reaction process, and the Co atom center is favorable for charging process. Theoretical calculations combined with experiments reveal that this excellent bifunctional catalytic activity originates from the diatomic synergy between Fe and Co atom. As a result, the assembled cells exhibit the high rate performance (the discharge specific capacity achieves 688 mAh g −1 at 5 C) and the excellent cycle stability (the capacity decay rate is 0.018% for 1000 cycles at 1 C). The slow redox kinetics of polysulfides and the difficulties in decomposition of Li 2 S are two serious obstacles to lithium-sulfur batteries. Here, the authors report an isolated Fe-Co heteronuclear diatomic catalyst to achieve high efficiency bifunctional catalysis for lithium-sulfur batteries.

With promises for high specific energy, high safety and low cost, the all-solid-state lithium–sulfur battery (ASSLSB) is ideal for next-generation energy storage 1 , 2 , 3 , 4 – 5 . However, the poor rate performance and short cycle life caused by the sluggish solid–solid sulfur redox reaction (SSSRR) at the three-phase boundaries remain to be solved. Here we demonstrate a fast SSSRR enabled by lithium thioborophosphate iodide (LBPSI) glass-phase solid electrolytes (GSEs). On the basis of the reversible redox between I − and I 2 /I 3 − , the solid electrolyte (SE)—as well as serving as a superionic conductor—functions as a surficial redox mediator that facilitates the sluggish reactions at the solid–solid two-phase boundaries, thereby substantially increasing the density of active sites. Through this mechanism, the ASSLSB exhibits ultrafast charging capability, showing a high specific capacity of 1,497 mAh g −1 sulfur on charging at 2C (30 °C), while still maintaining 784 mAh g −1 sulfur at 20C. Notably, a specific capacity of 432 mAh g −1 sulfur is achieved on charging at an extreme rate of 150C at 60 °C. Furthermore, the cell demonstrates superior cycling stability over 25,000 cycles with 80.2% capacity retention at 5C (25 °C). We expect that our work on redox-mediated SSSRR will pave the way for developing advanced ASSLSBs that are high energy and safe. By using lithium thioborophosphate iodide glass-phase solid electrolytes in all-solid-state lithium–sulfur batteries, fast solid–solid sulfur redox reaction is demonstrated, leading to cells with ultrafast charging capability, superior cycling stability and high capacity.

Shuttling of lithium polysulfides and slow redox kinetics seriously limit the rate and cycling performance of lithium-sulfur batteries. In this study, Fe 3 O 4 -dopped carbon cubosomes with a plumber’s nightmare structure (SP-Fe 3 O 4 -C) are prepared as sulfur hosts to construct cathodes with high rate capability and long cycling life for Li-S batteries. Their three-dimensional continuous mesochannels and carbon frameworks, along with the uniformly distributed Fe 3 O 4 particles, enable smooth mass/electron transport, strong polysulfides capture capability, and fast catalytic conversion of the sulfur species. Impressively, the SP-Fe 3 O 4 -C cathode exhibits top-level comprehensive performance, with high specific capacity (1303.4 mAh g − 1 at 0.2 C), high rate capability (691.8 mAh gFe 3 O 4 1 at 5 C), and long cycling life (over 1200 cycles). This study demonstrates a unique structure for high-performance Li-S batteries and opens a distinctive avenue for developing multifunctional electrode materials for next-generation energy storage devices. Shuttling of lithium polysulfides and slow redox kinetics seriously limit the rate and cycling performance of lithium-sulfur batteries. Here, the authors report a Fe 3 O 4 nanoparticle doped mesoporous carbon cathode with a plumber’s nightmare structure that can achieve high-rate and long performance.

Solid polymer electrolytes (SPEs), which are favorable to form intimate interfacial contacts with electrodes, are promising electrolyte of choice for long-cycling lithium metal batteries (LMBs). However, typical SPEs with easily oxidized oxygen-bearing polar groups exhibit narrow electrochemical stability window (ESW), making it impractical to increase specific capacity and energy density of SPE based LMBs with charging cut-off voltage of 4.5 V or higher. Here, we apply a polyfluorinated crosslinker to enhance oxidation resistance of SPEs. The crosslinked network facilitates transmission of the inductive electron-withdrawing effect of polyfluorinated segments. As a result, polyfluorinated crosslinked SPE exhibits a wide ESW, and the Li|SPE|LiNi 0.5 Co 0.2 Mn 0.3 O 2 cell with a cutoff voltage of 4.5 V delivers a high discharge specific capacity of ~164.19 mAh g −1 at 0.5 C and capacity retention of ~90% after 200 cycles. This work opens a direction in developing SPEs for long-cycling high-voltage LMBs by using polyfluorinated crosslinking strategy. Solid polymer electrolytes are commonly used in lithium-metal batteries, but their capacity and energy density cannot be easily increased beyond a charging cut-off voltage of 4.5 V due to the presence of easily oxidized oxygen-bearing polar groups. Here, authors apply a polyfluorinated crosslinker to enhance the oxidation resistance to solve this issue

Covalent organic frameworks with designable periodic skeletons and ordered nanopores have attracted increasing attention as promising cathode materials for rechargeable batteries. However, the reported cathodes are plagued by limited capacity and unsatisfying rate performance. Here we report a honeycomb-like nitrogen-rich covalent organic framework with multiple carbonyls. The sodium storage ability of pyrazines and carbonyls and the up-to twelve sodium-ion redox chemistry mechanism for each repetitive unit have been demonstrated by in/ex-situ Fourier transform infrared spectra and density functional theory calculations. The insoluble electrode exhibits a remarkably high specific capacity of 452.0 mAh g −1 , excellent cycling stability (~96% capacity retention after 1000 cycles) and high rate performance (134.3 mAh g −1 at 10.0 A g −1 ). Furthermore, a pouch-type battery is assembled, displaying the gravimetric and volumetric energy density of 101.1 Wh kg −1 cell and 78.5 Wh L −1 cell , respectively, indicating potentially practical applications of conjugated polymers in rechargeable batteries. Covalent organic frameworks are receiving increasing attention as promising cathode materials for rechargeable batteries. Here the authors report a honeycomb-like nitrogen-rich COF design in which the pyrazines and carbonyls enable favorable redox chemistry and remarkable Na-ion storage performance.

Silicon is a promising anode material due to its high theoretical specific capacity, low lithiation potential and low lithium dendrite risk. Yet, the electrochemical performance of silicon anodes in solid-state batteries is still poor (for example, low actual specific capacity and fast capacity decay), hindering practical applications. Here the chemo-mechanical failure mechanisms of composite Si/Li 6 PS 5 Cl and solid-electrolyte-free silicon anodes are revealed by combining structural and chemical characterizations with theoretical simulations. The growth of the solid electrolyte interphase at the Si|Li 6 PS 5 Cl interface causes severe resistance increase in composite anodes, explaining their fast capacity decay. Solid-electrolyte-free silicon anodes show sufficient ionic and electronic conductivities, enabling a high specific capacity. However, microscale void formation during delithiation causes larger mechanical stress at the two-dimensional interfaces of these anodes than in composite anodes. Understanding these chemo-mechanical failure mechanisms of different anode architectures and the role of interphase formation helps to provide guidelines for the design of improved electrode materials. Although silicon anodes are promising for solid-state batteries, they still suffer from poor electrochemical performance. Chemo-mechanical failure mechanisms of composite Si|Li 6 PS 5 Cl and solid-electrolyte-free silicon anodes are now revealed and should help in designing improved electrodes.