Rechargeable aqueous zinc-ion batteries (AZIBs) have captured a surge of interest in recent years as a promising alternative for scalable energy storage applications owing to the intrinsic safety, affordability, environmental benignity, and impressive electrochemical performance. Despite the facilitated development of this technology by many investigations, however, its smooth implementation is still plagued by inadequate energy density and undesirable life span, which calls for an efficient and controllable cathode storage chemistry. Here, this review focuses on the key bottlenecks by offering a comprehensive summary of representative cathode materials and comparatively analyzing their structural features and electrochemical properties. Then, we critically present several feasible electrode design strategies to guide future research activities from a fundamental perspective for high-energy-density and durable cathode materials mainly in terms of interlayer regulation, defect engineering, multiple redox reactions, activated two-electron reactions, and electrochemical activation and conversion. Finally, we outline the remaining challenges and future perspectives of developing high-performance AZIBs.

What has been a crucial demand is that designing mighty cathode materials for aqueous zinc−ion batteries (AZIBs), which are vigorous alternative devices for large−scale energy storage by means of their high safety and low cost. Herein, a facile strategy is designed that combines oxygen defect engineering with polymer coating in a synergistic action. As an example, the oxygen−deficient hydrate vanadium dioxide with polypyrrole coating (Od−HVO@PPy) is synthesized via a one‐step hydrothermal method in which introducing oxygen vacancy in HVO is simultaneously realized during the in situ polymerization. Such a desirable material adjusts the surface adsorption and internal diffusion of Zn2+ demonstrated by electrochemical characterization and theoretical calculation results. Moreover, it also utilizes conductive polymer coating to improve electrical conductivity and suppress cathode dissolution. Therefore, the Od−HVO@PPy electrode delivers a preferable reversible capacity (337 mAh g−1 at 0.2 A g−1) with an impressive energy density of 228 Wh kg−1 and stable long cycle life. This enlightened design opens up a new modus operandi toward superior cathode materials for advanced AZIBs.

Use of catalytic materials is regarded as the most desirable strategy to cope with sluggish kinetics of lithium polysulfides (LiPSs) transformation and severe shuttle effect in lithium-sulfur batteries (LSBs). Single-atom catalysts (SACs) with 100 %a tom-utilization are advantagous in serving as anchoring and electrocatalytic centers for LiPSs.H erein, an ovel kind of tungsten (W) SACi mmobilized on nitrogendoped graphene (W/NG) with au nique W-O 2 N 2 -C coordination configuration and ah igh Wl oading of 8.6 wt %i s proposed by as elf-template and self-reduction strategy.T he local coordination environment of Watom endows the W/NG with elevated LiPSs adsorption ability and catalytic activity. LSBs equipped with W/NG modified separator manifest greatly improved electrochemical performances with high cycling stability over 1000 cycles and ultrahigh rate capability. It indicates high areal capacity of 6.24 mAh cm À2 with robust cycling life at ahigh sulfur mass loading of 8.3 mg cm À2 .

Sodium‐ion batteries (SIBs) have emerged as an alternative technology because of their merits in abundance and cost. Realizing their real applications, however, remains a formidable challenge. One is that among the limitations of anode materials, the alloy‐type candidates tolerate fast capacity fading during cycling. Here, a 3D framework superstructure assembled with carbon nanobelt arrays decorated with a metallic bismuth (Bi) nanospheres coated carbon layer by thermolysis of Bi‐based metal–organic framework nanorods is synthesized as an anode material for SIBs. Due to the unique structural superiority, the anode design promotes excellent sodium‐storage performance in terms of high capacity, excellent cycling stability, and ultrahigh rate capability up to 80 A g−1 with a capacity of 308.8 mAh g−1. The unprecedented sodium‐storage ability is not only attributed to the unique hybrid architecture, but also to the production of a homogeneous and thin solid electrolyte interface layer and the formation of uniform porous nanostructures during cycling in the ether‐based electrolyte. Importantly, deeper understanding of the underlying cause of the performance improvement is illuminated, which is vital to provide the theoretical basis for application of SIBs.

The search for large-capacity and high-energy-density cathode materials for aqueous Zn-ion batteries is still challenging. Here, an in situ electrochemical activation strategy to boost the electrochemical activity of a carbon-confined vanadium trioxide (V2O3@C) microsphere cathode is demonstrated. Tunnel-structured V2O3 undergoes a complete phase transition to a layered, amorphous, and oxygen-deficient Zn0.4V2O5–m ·nH2O on the first charge, thus allowing subsequent (de)­intercalation of zinc cations on the basis of the latter structure, which can be regulated by the amount of H2O in the electrolyte. The electrode thus delivers excellent stability with a significantly high capacity of 602 mAh g–1 over 150 cycles upon being subjected to a low-current-rate cycling, as well as a high-energy density of 439.6 Wh kg–1 and extended life up to 10000 cycles with a 90.3% capacity retention. This strategy will be exceptionally desirable to achieve ultrafast Zn-ion storage with high capacity and energy density.

The practical application of lithium-sulfur batteries is still limited by the lithium polysulfides (LiPSs) shuttling effect on the S cathode and uncontrollable Li-dendrite growth on the Li anode. Herein, elaborately designed WSe 2 flakelets immobilized on N-doped graphene (WSe 2 /NG) with abundant active sites are employed to be a dual-functional host for satisfying both the S cathode and Li anode synchronously. On the S cathode, the WSe 2 /NG with a strong interaction towards LiPSs can act as a redox accelerator to promote the bidirectional conversion of LiPSs. On the Li anode, the WSe 2 /NG with excellent lithiophilic features can regulate the uniform Li plating/stripping to mitigate the growth of Li dendrite. Taking advantage of these merits, the assembled LiÀ S full batteries exhibit remarkable rate performance and stable cycling stability even at a higher sulfur loading of 10.5 mg cm À 2 with a negative to positive electrode capacity (N/ P) ratio of 1.4 : 1.

Herein, NbN nanocrystals immobilized on N-doped carbon nanosheets to functionalize a polypropylene (PP) membrane (NbN@NC/PP) with a thin coating of only 4 µm are designed and synthesized. The functional modifier layer allows for sulfur-involved transformations and also lithium plating behaviors. On the one hand, the sulfur cell with NbN@NC/PP separator exhibits excellent cycling stability and rate capacity. The good electrochemical performance partially results from the strong chemical interactions between NbN and lithium polysulfides via the formation of NbS and NLi bonds, which is proven by the first-principles calculations and X-ray photoelectron spectroscopy analyses. The formation of tiny nanoscrystals (<2 nm) and clusters tends to maximize the surface of NbN to interact with polysulfides and enable the effective catalysis over the sulfur-involved reactions. The higher exchange current density and Li + diffusion coefficient of NbN@NC/ PP cells experimentally verify that the introduction of NbN indeed catalytically accelerates the reaction kinetics. On the other hand, the performance of Li// Li symmetric cells demonstrates that the NbN@NC modifier layer can well induce homogeneous lithium deposition. This work confirms the application potential of NbN in lithium-sulfur batteries and encourages the exploration of prospective nitrides to engineer high performance next-generation batteries.

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