Layered double hydroxides (LDHs) have great advantages in the domain of stored energy because of the exchangeable anions and large specific surface area. Nevertheless, the shortcomings of poor electrical conductivity,...

Due to its high safety and low cost, aqueous Zn-ion batteries (AZIBs) have become one of the most promising energy storage devices. However, the development of a stable cathode with fast kinetics and high-energy density is crucial to realize AZIBs for large-scale application. In this work, KOH-induced oxygen-deficient VO2 (K-VO2) was developed by activating doughnutlike VO2 by KOH. Benefiting from the combination of a unique morphology with abundant active sites and the oxygen vacancy, increasing the interlayer spacing, both improved kinetics and enhanced Zn-ion storage capability in the VO2 cathode are achieved. The optimized K-VO2-3:4 delivers a specific capacity of 260.9 mA h g–1 at 0.2 A g–1, an excellent high-rate capability of 166.1 mA h g–1 at 5 A g–1, and long-term cyclic stability with a capacity retention of 88.1% after 3000 cycles. The electrochemical performance of K-VO2-3:4 has been greatly improved compared with untreated VO2. The KOH activation strategy proposed here also presents an encouraging pathway for developing other high-energy and stable cathodes.

Although the advantages of transition metal oxides (TMOs) have low cost, convenient synthesis and high capacity, the severe volume expansion and modest conductivity restrain its extensive applications. In this work,...

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