A dual-functional circular organic small molecule for dendrite-free zinc metal batteries with long-term cycling

Aqueous zinc (Zn) metal batteries have received widespread attention for their high safety and low cost, but some problems during cycling such as dendrite growth, hydrogen evolution reaction , and corrosion reaction hinder their application. Herein, the organic small molecule 1.4.7.10-tetraazacyclododecane (cyclen) is introduced as an effective additive in zinc sulfate electrolyte. Due to abundant N and cyclic structure, cyclen not only has stronger coordination than H 2 O molecules, resulting in the changed solvation structure of Zn 2+ , but also preferentially adsorbs onto the Zn (002) plane, inducing uniform deposition of Zn 2+ . Therefore, the Zn||Zn symmetrical cell achieved long-term cycling of over 2400 h at 1 mA cm −2 and 1 mAh cm −2 . Moreover, the performance of Zn||V 2 O 5 full cell was improved by the addition of cyclen, with a capacity retention rate of 90.9 % after 2000 cycles under 3 A g −1 .