Advancing high capacity 3D VO2(B) cathodes for improved zinc-ion battery performance

Abstract

Aqueous zinc-ion batteries (AZIBs) have gained attention for their intrinsic characteristics, driven by key advantages, such as cost-effectiveness, widespread availability of zinc, and reduced environmental impact, making AZIBs a promising alternative to lithium-based batteries, with potential applications in mini-grid and mini off-grid energy systems. However, achieving high capacity is crucial for AZIBs, driving the research focus towards developing advanced cathode materials. Vanadium dioxide (VO₂(B)) has emerged as a promising cathode material for AZIBs, owing to its large tunnel-like framework that accommodates Zn²⁺ ions for enhanced capacity. The overall performance of cathode materials depends not only on their inherent properties but also on their synthesis methods, electrode processing techniques, and achievement of ultra-high mass loading for 3D electrodes. In this study, we explore the optimization of VO₂(B) cathodes through refined synthesis approaches, various electrode processing methods, and the development of 3D electrodes with ultrahigh mass loading. As a result, we achieved significant improvements in specific capacity, from 310 mA h g⁻¹ to 500 mA h g⁻¹, through parameter tuning. Additionally, our optimized cathodes demonstrated a stable capacity retention of 71.5% after 1000 cycles. We also developed ultra-high mass loading cathodes of 24 g cm⁻², achieving an areal capacity of 4.6 mA h cm⁻², with a stability of 81.5% after 1000 cycles. This work provides a comprehensive approach to obtaining high-capacity cathodes, contributing to the advancement of reliable and high-performance AZIBs.