Electrochemical Zinc Intercalation in Lithium Vanadium Oxide: A High-Capacity Zinc-Ion Battery CathodeRechargeable zinc-ion batteries (ZIBs) with high energy densities appear promising to meet the increasing demand for safe and sustainable energy storage devices. However, electrode research on this low-cost and green system are faced with stiff challenges of identifying materials that permit divalent ion-intercalation/deintercalation. Herein, we present layered-type LiV3O8 (LVO) as a prospective intercalation cathode for zinc-ion batteries (ZIBs) with high storage capacities. The detailed phase evolution study during Zn intercalation using electrochemistry, in situ XRD, and simulation techniques reveals the large presence of a single-phase domain that proceeds via a stoichiometric ZnLiV3O8 phase to reversible solid–solution ZnyLiV3O8 (y > 1) phase. The unique behavior, which is different from the reaction with lithium, contributes to high specific capacities of 172 mAh g–1 and amounts to 75% retention of the maximum capacity achieved in 65 cycles with 100% Coulombic efficiency at a current density of 133 mA g–1. The remarkable performance makes the development of this low-cost and safe battery technology very promising, and this study also offers opportunities to enhance the understanding on electrochemically induced metastable phases for energy storage applications.
Na<sub>2</sub>V<sub>6</sub>O<sub>16</sub>·3H<sub>2</sub>O Barnesite Nanorod: An Open Door to Display a Stable and High Energy for Aqueous Rechargeable Zn-Ion Batteries as CathodesOwing to their safety and low cost, aqueous rechargeable Zn-ion batteries (ARZIBs) are currently more feasible for grid-scale applications, as compared to their alkali counterparts such as lithium- and sodium-ion batteries (LIBs and SIBs), for both aqueous and nonaqueous systems. However, the materials used in ARZIBs have a poor rate capability and inadequate cycle lifespan, serving as a major handicap for long-term storage applications. Here, we report vanadium-based Na2V6O16·3H2O nanorods employed as a positive electrode for ARZIBs, which display superior electrochemical Zn storage properties. A reversible Zn2+-ion (de)intercalation reaction describing the storage mechanism is revealed using the in situ synchrotron X-ray diffraction technique. This cathode material delivers a very high rate capability and high capacity retention of more than 80% over 1000 cycles, at a current rate of 40C (1C = 361 mA g–1). The battery offers a specific energy of 90 W h kg–1 at a specific power of 15.8 KW kg–1, enlightening the material advantages for an eco-friendly atmosphere.