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 and make 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 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, which accommodates Zn²⁺ ions for enhanced capacity. The overall performance of cathode materials depends not only on their inherent properties, but also on synthesis methods, electrode processing techniques, and achieving 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 mAh g-1 to 500 mAh 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 areal capacity of 4.6 mAh 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.