Spent shell as a calcium source for constructing calcium vanadate for high-performance Zn-ion batteries.

In this article, waste shell is directly used as a raw material to synthesize CaVO as a cathode for aqueous zinc ion batteries. The obtained cathode material exhibits better performance than that of CaVO prepared from pure calcium carbonate as a raw material. At 0.1 A g, the CaVO prepared by spent shell as a calcium source displays a highly reversible discharge capacity of 373 mA h g. A high initial discharge capacity of 177.7 mA h g can be gained at 5.0 A g, and the specific capacity remains at 133.3 mA h g with a capacity retention of 75% after 3000 cycles. This work may spark inspiration for energy storage and generate more effective routes for recycling solid waste.