A Rechargeable Zinc–Copper Voltaic Battery Built from Cost-Effective Electrodes and Electrolytes

The zinc–copper (Zn-Cu) voltaic battery is the first battery made in human history, but the Cu2+ dissolution issue leads to the reaction’s irreversibility. To tackle this challenge, solid-state electrolytes, ion exchange membranes, and functional electrolytes have been proposed to mitigate the Cu2+ dissolution; however, these approaches incur limitations like cell complexity, high cost, and anode corrosion. Herein, we develop a simple yet effective strategy to mitigate Cu2+ dissolution and build a rechargeable voltaic battery from cost-effective materials, including commercially available micro-copper powders and non-corrosive zinc acetate electrolyte. Importantly, the near-neutral Zn(Ac)2 electrolyte provides some amounts of hydroxide and facilitates the Cu2O/Cu solid–solid conversion reaction, thereby inhibiting the generation of soluble Cu2+ ions. As a result, the Zn-Cu battery exhibits a reversible capacity of ~130 mAh g−1, a feasible voltage of 0.87 V, and a stable cycling life over 100 cycles. Our work provides a feasible strategy for developing rechargeable and cost-effective Zn-Cu batteries.