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Implementing fast‐charging lithium‐ion batteries (LIBs) is severely hindered by the issues of Li plating and poor rate capability for conventional graphite anode. Wadsley–Roth phase TiNb2O7 is regarded as a promising anode candidate to satisfy the requirements of fast‐charging LIBs. However, the unsatisfactory electrochemical kinetics resulting from sluggish ion and electron transfer still limit its wide applications. Herein, an effective strategy is proposed to synchronously improve the ion and electron transfer of TiNb2O7 by incorporation of oxygen vacancy and N‐doped graphene matrix (TNO−x@N‐G), which is designed by combination of solution‐combustion and electrostatic self‐assembly approach. Theoretical calculations demonstrate that Li+ intercalation gives rise to the semi‐metallic characteristics of lithiated phases (LiyTNO−x), leading to the self‐accelerated electron transport. Moreover, in situ X‐ray diffraction and Raman measurements reveal the highly reversible structural evolution of the TNO−x@N‐G during cycling. Consequently, the TNO−x@N‐G delivers a higher reversible capacity of 199.0 mAh g−1 and a higher capacity retention of 86.5% than those of pristine TNO (155.8 mAh g−1, 59.4%) at 10 C after 2000 cycles. Importantly, various electrochemical devices including lithium‐ion full battery and hybrid lithium‐ion capacitor by using the TNO−x@N‐G anode exhibit excellent rate capability and cycling stability, verifying its potential in practical applications. [ABSTRACT FROM AUTHOR]

Developing advanced electrode materials with high stability and high ion-diffusion rate is vital for the success of high-rate lithium-ion batteries (LIBs). However, the commonly used modification strategies such as carbon coating, nanoarchitecture engineering, and introducing oxygen vacancies are unavoidably meeting with the problems of high cost and complicated preparation process. Herein, we report cation-mixing effect enhanced fast Li+ storage in Wadsley-Roth phase Fe-Ti-Nb oxide (FTNO) materials by a facile solution combustion method. Co-existence of Fe3+ and Ti4+ in the crystallographic shear structure leads to enhanced cation-mixing effect with cations short-range order (SRO) in FTNO materials, thus resulting in outstanding capabilities of fast Li+ storage/diffusion, robust structure and low charge transfer resistance compared with the analogues of FeNb11O29 and Ti2Nb10O29. Consequently, a high-capacity retention of 71.8% is achieved upon 10 000 cycles at 10 C. Most importantly, the feasibilities of FTNO are also systematically verified in various practical electrochemical energy storage devices containing conventional lithium-ion full battery (FTNOǁLiFePO4), high-power lithium-ion hybrid capacitor [FTNOǁactive carbon (AC)], and novel dual-ion battery [FTNOǁmesocarbon microbeads (MCMB)]. It is worth noting that the FTNOǁMCMB with high output voltage of 3 V delivers a capacity of 105.7 mAh g−1, implying a great potential of FTNO applied in dual-ion batteries. [ABSTRACT FROM AUTHOR]

Rechargeable zinc‐ion batteries (ZIBs) have recently attracted attention for applications in energy storage systems owing to their intrinsic safety, low cost, environmental compatibility, and competitive gravimetric energy density. To enable the practical applications of ZIBs, their energy density must be equivalent to the existing commercial lithium‐ion batteries. To acquire high‐energy density, increasing the operating voltage of the battery is undoubtedly an effective method, which demands cathode material to exhibit a high voltage versus Zn2+/Zn, while matching a highly reversible anode and an electrolyte with a sufficiently wide electrochemical stability window. This review focuses on the design strategies and challenges towards high‐voltage ZIBs. First, the basic electrochemistry of ZIBs and the recent progress in various high‐voltage cathode materials for ZIBs, including Prussian blue analogs, polyanionic compounds, and metal‐based oxides are introduced. The challenges and corresponding countermeasures of these materials are discussed, while strategies to further improve the cathode operating voltage, influence factors of voltage in the redox reaction, and energy storage mechanism are also illustrated. The following section describes the strategies towards high‐performance Zn anode, and summarizes the electrolytes that can help increase the battery voltage. The final section outlines the potential development in ZIBs. [ABSTRACT FROM AUTHOR]

Lithium ion batteries (LIBs) at present still suffer from low rate capability and poor cycle life during fast ion insertion/extraction processes. Searching for high‐capacity and stable anode materials is still an ongoing challenge. Herein, a facile strategy for the synthesis of ultrathin GeS2 nanosheets with the thickness of 1.1 nm is reported. When used as anodes for LIBs, the two‐dimensional (2D) structure can effectively increase the electrode/electrolyte interface area, facilitate the ion transport, and buffer the volume expansion. Benefiting from these merits, the as‐synthesized GeS2 nanosheets deliver high specific capacity (1335 mAh g−1 at 0.15 A g−1), extraordinary rate performance (337 mAh g−1 at 15 A g−1) and stable cycling performance (974 mAh g−1 after 200 cycles at 0.5 A g−1). Importantly, our fabricated Li‐ion full cells manifest an impressive specific capacity of 577 mAh g−1 after 50 cycles at 0.1 A g−1 and a high energy density of 361 Wh kg−1 at a power density of 346 W kg−1. Furthermore, the electrochemical reaction mechanism is investigated by the means of ex‐situ high‐resolution transmission electron microscopy. These results suggest that GeS2 can use to be an alternative anode material and encourage more efforts to develop other high‐performance LIBs anodes. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries have attracted interest as an alternative to lithium‐ion batteries because of the abundance and cost effectiveness of sodium. However, suitable anode materials with high‐rate and stable cycling performance are still needed to promote their practical application. Herein, three‐dimensional Na2Ti3O7 nanowire arrays with enriched surface vacancies endowed by phosphorus doping are reported. As anodes for sodium‐ion batteries, they deliver a high specific capacity of 290 mA h g−1at 0.2 C, good rate capability (50 mA h g−1at 20 C), and stable cycling capability (98 % capacity retention over 3100 cycles at 20 C). The superior electrochemical performance is attributed to the synergistic effects of the nanowire arrays and phosphorus doping. The rational structure can provide convenient channels to facilitate ion/electron transport and improve the capacitive contributions. Moreover, the phosphorus‐doping‐induced surface vacancies not only provide more active sites but also improve the intrinsic electrical conductivity of Na2Ti3O7, which will enable electrode materials with excellent sodium storage performance. This work may provide an effective strategy for the synthesis of other anode materials with fast electrochemical reaction kinetics and good sodium storage performance. [ABSTRACT FROM AUTHOR]

Owing to the high theoretical capacity (394 mAh g−1) and appropriate lithiation voltage (0.5–1.0 V vs Li+/Li), Li3VO4 is highly regarded as an attractive anode candidate for high‐safety lithium‐ion batteries. However, its high‐rate performance is seriously restricted by the sluggish electrode kinetics. To address these problems, we synthesize cowpea‐like Li3VO4@C nanowires through a facile electrospinning method. In this well‐designed structure, Li3VO4 nanocrystals are uniformly encapsulated in conductive carbon nanofibers just like peas in their pods. The 1D morphology with high electronic conductivity can afford high Li+ ions diffusion rate and fast surface charge storage mechanism, leading to significantly enhanced electrochemical kinetics. Even after 1000 cycles at 2 A g−1, the reversible capacity of cowpea‐like Li3VO4@C nanowires can be maintained at 318.0 mAh g−1 without obvious capacity decay. [ABSTRACT FROM AUTHOR]

It is still a great challenge to develop the long-life anode active materials for lithium ion batteries (LIBs) due to those issues resulting from the volumetric expansion of electrode materials during lithiation. Herein, we report the preparation of N-doped carbon (N-C) nanotubes encapsulated MnO nanoparticles with the size of 20–50 nm by hydrolysis of metal coordination polymers (MCPs) in nitrogen gas, which is different from typical metal oxide/C core/shell nanostructures with conformal coating. The MnO/N-C nanotubes with an empty space between the nanoparticles allow for more volume expansion, which can effectively overcome existed issues such as MnO dissolution, disintegration, aggregation and volumetric expansion during the lithium ions insertion/extraction. When evaluated as electrode materials for lithium-ion batteries, the MnO/N-C nanotubes exhibit discharge and charge capacities of 1557.5 and 1171.0 mAh g −1 in the initial cycle at 100 mA g −1 , respectively. And more impressively, the reversible capacity of 450.2 mAh g −1 is remained after increasing the current density to 5 Ag −1 . Especially, the capacity steadily maintains at 804 mAh g −1 even after 100 charge-discharge cycles at 1 Ag −1 . [ABSTRACT FROM AUTHOR]

Frontispiece: Post-Lithium-Ion Battery Era: Recent Advances in Rechargeable Potassium-Ion Batteries Keywords: alloy-based materials; carbon electrodes; electrochemistry; layered metal oxides; organic materials; potassium ion batteries EN alloy-based materials carbon electrodes electrochemistry layered metal oxides organic materials potassium ion batteries 1 1 1 01/09/21 20210107 NES 210107 B Potassium-ion batteries b (PIBs) have become a promising energy storage device for large-scale energy storage systems. Alloy-based materials, carbon electrodes, electrochemistry, layered metal oxides, organic materials, potassium ion batteries. [Extracted from the article]

Exploring electrode materials with rapid, safe, and stable Li-(de)intercalation is of vital importance for developing next-generation lithium-ion batteries (LIBs) and hybrid lithium ion capacitors (LICs). Niobium-based compounds have attracted extensive interest for fast lithium storage due to their unique crystalline structure and high safety. This review provides a comprehensive overview of Nb-based electrode materials and their recent research progress. According to the different constitutions present in Nb-based anode materials, Nb–O, Nb–C, Nb–N and M-Nb-O (M = metal elements) systems are systematically discussed. Their physicochemical features and intrinsic disadvantages including low conductivities and sluggish ion diffusion rates impede the practical application are concluded. Then the design of Nb-based electrode architectures using nanosizing, conductive layer-coating, foreign atom doping, and their synergetic effects are also discussed since they play essential roles in enhancing the intrinsic capabilities. Finally, feasible strategies for improving the electrochemical capabilities of high-rate niobium-based electrodes are also briefly introduced. With this review, we hope to provide reference values for researchers or general readers, and to inspire more explorative work on building effective Nb-based energy storage materials for lithium-ion batteries and hybrid lithium ion capacitors. • Various niobium-based materials for lithium ion storage are systematacially discussed. • Lithiation mechanisms and synthetic methods of Nb-based compounds are shown. • Strategies for enhancing rate capability of Nb-based materials are outlined. [ABSTRACT FROM AUTHOR]

Recently, aqueous zinc ion batteries have emerged as attracting alternatives to conventional lithium ion batteries with the merits of low cost and operation safety. However, the Zn host material with fast Zn kinetic and could sustain reversible Zn2+ insertion and extraction is still a big challenge. Here, a nanowire morphology (NH 4) 2 V 6 O 16 ·1.5H 2 O nanostructures fabricated via a facile microwave-assisted hydrothermal reaction are presented as a prospective zinc ion battery cathode. The trapped Zn(H 2 O) 6 2+ ions in the initial discharge process not only help make the vanadium oxide layer stable but also provide enough interlayer distance for fast ion kinetics during the preceding intercalation/deintercalation process. Owing to the large interplane distance pillared by cations, crystal water molecular and the high diffusion coefficient of (NH 4) 2 V 6 O 16 ·1.5H 2 O cathode, it presents an excellent low temperature performance (120 mAh g−1 at a current density of 0.1 A g−1) and highly reversible cycling performance (75% after 10000 cycles at 8 A g−1). The outstanding performance, the easy fabrication along with the low-cost feature make (NH 4) 2 V 6 O 16 ·1.5H 2 O cathode reliable in aqueous zinc ion battery application. • Layered NVO were fabricated by a microwave-assisted hydrothermal reaction. • The NVO cathode exhibits high rate performance and long-term stability. • The NVO presents an excellent low temperature performance. [ABSTRACT FROM AUTHOR]