With the merit of high capacity, high safety, and low cost, zinc-ion batteries (ZIBs) possess huge application potential in the domain of large-scale energy storage. However, due to the relatively narrow voltage window and large lattice distortion of cationic redox reaction, ZIBs tend to present low energy density, poor kinetics, and unstable cyclic performance. Anion chemistry seems to provide a novel strategy to solve these issues from different aspects, such as enhanced operating voltage, extra capacity contribution, and boosted reaction kinetics. Considering the significance of this theory and the lack of relevant literatures, herein, in-depth comprehension of anionic chemistry and its positive effects on zinc storage performance have been emphasized and summarized. This review aims to present a full scope of anionic chemistry and furnish systematic cognition for rational design of advanced ZIBs with high energy density. Furthermore, insightful analysis and perspectives based on the current research status also have been proposed, which may point out some scientific suggestions and directions for the future research.

Low-cost preparation methods for cathodes with high capacity and long cycle life are crucial for commercializing potassium-ion batteries (PIBs). Presently, the charging/discharging strain that develops in the active cathode material of PIBs causes cracks in the particles, leading to a sharp capacity fade. Here, to abate the strain release and the need for an industrially relevant process, a simple low-cost co-precipitation method for synthesizing yolk–shell P3-type K_0.5[Mn_0.85Ni_0.1Co_0.05]O₂ (YS-KMNC) was reported. As cathode material for PIBs, the YS-KMNC delivers a high reversible capacity (96 mAh g^–1 at 20 mA g^–1) and excellent cycle stability (80.5% retention over 400 cycles at a high current density of 200 mA g^–1). More importantly, a full battery assembled with the YS-KMNC cathode and a commercial graphite anode exhibits a high operating voltage (0.5-3.4 V) and an excellent cycling performance (84.2% retention for 100 cycles at 100 mA g^–1). Considering the low-cost, simple production process and high performance of YS-KMNC cathode, this work could pave the way for the commercial development of PIBs.

Sodium superionic conductor (NASICON)-type compounds have been regarded as promising cathodes for sodium-ion batteries (SIBs) due to their favorable ionic conductivity and robust structural stability. However, their high cost and relatively low energy density restrict their further practical application, which can be tailored by widening the operating voltages with earth-abundant elements such as Mn. Here, we propose a rational strategy of infusing Mn element in NASICON frameworks with sufficiently mobile sodium ions that enhances the redox voltage and ionic migration activity. The optimized structure of Na_3.5Mn_0.5V_1.5(PO₄)₃/C is achieved and investigated systematically to be a durable cathode (76.6% capacity retention over 5,000 cycles at 20 C) for SIBs, which exhibits high reversible capacity (113.1 mAh·g^-1 at 0.5 C) with relatively low volume change (7.6%). Importantly, its high-areal-loading and temperature-resistant sodium ion storage properties are evaluated, and the full-cell configuration is demonstrated. This work indicates that this Na_3.5Mn_0.5V_1.5(PO₄)₃/C composite could be a promising cathode candidate for SIBs.

Vanadium oxides with a layered structure are promising candidates for both lithium-ion batteries and sodium-ion batteries (SIBs). The self-template approach, which involves a transformation from metal-organic frameworks (MOFs) into porous metal oxides, is a novel and effective way to achieve desirable electrochemical performance. In this study, porous shuttle-like vanadium oxides (i.e., V₂O₅, V₂O₃/C) were successfully prepared by using MIL-88B (Ⅴ) as precursors with a specific calcination process. As a proof-of-concept application, the asprepared porous shuttle-like V₂O₃/C was used as an anode material for SIBs. The porous shuttle-like V₂O₃/C, which had an inherent layered structure with metallic behavior, exhibited excellent electrochemical properties. Remarkable rate capacities of 417, 247, 202, 176, 164, and 149 mAh·g^-1 were achieved at current densities of 50, 100, 200, 500, 1, 000, and 2, 000 mA·g^-1, respectively. Under cycling at 2 A·g^-1, the specific discharge capacity reached 181 mAh·g^-1, with a low capacity fading rate of 0.032% per cycle after 1, 000 cycles. Density functional theory calculation results indicated that Na ions preferred to occupy the interlamination rather than the inside of each layer in the V₂O₃. Interestingly, the special layered structure with a skeleton of dumbbell-like V–V bonds and metallic behavior was maintained after the insertion of Na ions, which was beneficial for the cycle performance. We consider that the MOF precursor of MIL-88B (Ⅴ) can be used to synthesize other porous V-based materials for various applications.