In Situ Electrochemical Activation Strategy toward Organic Cation Preintercalated Layered Vanadium-Based Oxide Cathode for High-Performance Aqueous Zinc-Ion Batteries

Layered vanadium-based oxides with preintercalated metal cations are attracting extensive attention as highly promising candidates for aqueous zinc-ion batteries (AZIBs) due to the increase in structural stability originating from the pillar effect. However, the strong electrostatic interaction between the rigid metal cation pillars and zinc ions results in sluggish ionic transport, thereby limiting the high-rate performance. Herein, a layered vanadium-based oxide with protonated 1,4-diaminobutane organic cation (BDA) pillars is designed as a cathode material for AZIBs. Due to the larger radius and stronger interconnection with the VO layers, the organic cation guests acting as pillars not only ensure a large interlayer space but also significantly enhance the structural stability of the layered host. Furthermore, by adopting an in situ electrochemical activation strategy, the quantitative control of the organic cation pillar content is effectively achieved. The irreversible removal of partial pillar guests not only weakens its steric buckling effects on the zinc ion but also provides more effective sites for zinc ion storage. As anticipated, the resulting (H₃N(CH₂)₄NH₃)[V₆O₁₄] (BDA-VO) electrode material exhibits an excellent electrochemical property with a high reversible specific capacity of 345 mAh g^-1 at a current density of 0.1 A g^-1 and an excellent cycle stability with 93.2% capacity retention over 2000 cycles at 5 A g^-1.