Multicomponent hierarchical Cu-based advanced cathode for ultrahigh capacity rechargeable Cu-Zn battery

Rechargeable aqueous Zn-based batteries (RAZBs) have emerged as a practically attractive option for large-scale energy storage applications due to their cost-effectiveness, safety, eco-friendliness, and high theoretical capacity. Nonetheless, the application of RAZBs at the grid scale is restricted by the drawbacks of cathode that exhibit low capacities and poor durability. In this work, a multicomponent hierarchical Cu@CuO@Cu2O cathode with superior electrochemical energy storage performance has been successfully synthesized by a fairly simple calcination method. Benefiting from its large active area, fast ion diffusion channel, high conductivity, and synergetic effect between different components, the resulting Cu@CuO@Cu2O electrode exhibits ultrahigh specific capacity (40.2 mAh cm- 2, 402 mAh cm- 3 at 10 mA cm- 2), excellent rate capability (24.8 mAh cm- 2, 248 mAh cm- 3 at 100 mA cm- 2) and satisfactory cycling durability (71.5 % capacity retention after 3800 cycles). To our knowledge, such high areal/volumetric specific capacity ranks top among previously reported Cu-based electrode and other aqueous electrodes. Furthermore, the fabricated Cu@CuO@Cu2O//Zn battery achieves an extraordinary energy density of 24.5 mWh cm- 2 and a remarkable cyclic capability of 91 % capacity retention after 3000 cycles, highlighting its potential for large-scale energy storage in RAZBs.