Cation-Engineered NaCaVOH Microspheres with Enhanced Stability for High-Capacity and Low-Temperature Aqueous Zinc-Ion Batteries

Abstract

Vanadium-based oxides are promising cathodes for aqueous zinc-ion batteries (AZIB) but suffer from inferior structural stability and sluggish Zn2+ diffusion. Herein, Na0.069Ca1.06V10O24·3.2H2O (NaCaVOH) microspheres were rationally designed and synthesized via a facile, scalable, and low-energy one-step hydrothermal route by regulating Na+/Ca2+ co-insertion into the layered vanadium oxide. The dual cations act as pillars to stabilize the layered structure, while structural water lubricates ion transport to accelerate Zn2+ (de)intercalation, realizing a synergistic enhancement of performance and sustainability. The NaCaVOH cathode delivers a high reversible capacity of 327 mA h g–1 at 0.5 A g–1, 54.6% capacity retention from 0.5 to 10 A g–1, and 90% capacity retention over 8000 cycles at 10 A g–1. Impressively, it exhibits exceptional wide-temperature adaptability, maintaining 91.82–52.66% of room-temperature capacity from 10 to –30 °C with 97.99% capacity recovery upon reheating to 25 °C and sustaining 100% capacity over 800 cycles at -20 °C. This work offers a feasible and cost-effective cation-engineering strategy for developing sustainable, high-performance, and wide-temperature vanadium-based cathodes, advancing the practical application of AZIBs in low-carbon industrial energy storage systems.