Layered (NH4)1.32Na0.95V6O16·1.88H2O Nanobelt as a High Performance Cathode Material for Aqueous Zinc-Ion Batteries

Abstract

Rechargeable aqueous zinc-ion batteries (AZIBs) have attracted increasing attention owing to their high theoretic capacity and safe nonflammable electrolytes. Vanadium-based cathode materials have emerged as promising candidates for AZIBs owing to their multivalent redox chemistry and expanded interlayer architectures for high specific capacity. In this work, (NH₄)_1.32Na_0.95V₆O₁₆·1.88H₂O (NNVO) is developed as a high performance cathode material for AZIBs. In this work, Na⁺ not only serves as a pillar to increase the interlayer spacing but also acts as a guest sacrificial template for intercalated Zn²⁺ ions. The residue Na⁺ still works as a pillar to support the vanadium layers, and the replaced Na⁺ by Zn²⁺ works as a guest sacrificial template to make it easier for the host accommodating Zn²⁺, thereby stabilizing the interlayer spacing. As a result, The NNVO cathode exhibits a good rate capability, achieving a capacity of 460.2 mAh g^–1 at 0.1 A g^–1 and 195 mAh g^–1 at 5 A g^–1, a good stability with 89.6% retention after 3500 cycles at 5 A g^–1. This work provides a reference for engineering cathode materials in aqueous batteries.