A high capacity TeO2 cathode for aqueous zinc-ion batteries

Aqueous zinc ion batteries (AZIBs) with high safety, low cost, and environmental friendliness are an important candidate for future electrochemical energy storage systems. Exploring high-capacity cathodes for AZIBs remains rewarding and challenging. Here we first developed mixed tellurium oxide/acetylene black cathode with high capacity for aqueous zinc-ion storage. The cathode exhibits excellent rate performance of 517 and 429 mAh/g at 400 and 3000 mA g−1, respectively. Composite experiments confirmed the reaction mechanism of the two-step conversion discharge process from tellurium oxide to tellurium to zinc telluride. The revelation of such a high-capacity cathode with mechanism provides new insights into the advancement of AZIBs.