Decoupled tin–silver batteries with long cycle life and power output stability based on dendrite-free tin anode and halide insertion cathode chemistry

Conventional Ag-Zn batteries have historically faced the challenge of poor cycling stability, rooting in issues associated with Ag cathode dissolution and Zn anode dendrites. Herein, we present a pioneering decoupled Sn-Ag cell, which features two chambers separated by a cation-exchange membrane, containing a dendrite-free Sn metal anode immersed in an alkaline anolyte, and an Ag nanowires/carbon nanotube 3D thick-network cathode in a neutral catholyte. Benefiting from the achieved high electroplating/stripping stability of the metallic Sn anode in the alkaline electrolyte and the electrochemical reversibility of the Ag/AgCl cathode redox couple in the neutral electrolyte, the assembled decoupled Sn-Ag cell demonstrates superior cycling stability, retaining 82.4% of its initial capacity even after 4000 cycles (2 mA cm⁻²), significantly outperforming both the contrastive decoupled Ag-Zn cell (1500 cycles) and conventional alkaline Ag-Zn batteries (<100 cycles). Furthermore, through the integration of the decoupled Sn-Ag battery with solar cells and power management circuits, an intelligent power system of photovoltaic charging and energy storage was designed, demonstrating its practical viability through maintenance-free charging-discharging during day-night cycles. This research not only significantly increases the lifespan of Ag-batteries with an ultra-flat voltage platform but also opens avenues for the decoupled design of a wide variety of aqueous battery systems. © 2024 The Author(s). Published by the Royal Society of Chemistry.