Constructing the coordination and shielding layers with sodium benzenesulfonate to stabilize the Zn anode

Abstract

Aqueous Zinc-ion batteries (AZBs) are most expected as a substitute for lithium-ion batteries (LIBs) among many energy storing devices owing to their distinct advantage of high security, environment-friendly, and low cost. However, Zn anodes encounter various obstruction, for instance, dendrite growth, hydrogen evolution, poor Columbic efficiency (CE), grossly impeded commercialization of AZBs. Herein, sodium benzenesulfonate (SBS) additive was introduced to 2 M ZnSO4, which can generate the coordination and shielding layers to optimize the solvated structure. The combination of bound water with Zn2+ was decreased, and the combination of Zn2+ with SO42− was efficiently promoted, thereby eases the generation of side reactions. Moreover, shielding effects caused by Na+ effectively reduces the formation of dendrites. Hence, the Zn//Zn symmetrical cells with the solvent added SBS exhibits excellence in reversibility and cycling life over 1900 h (0.5 mA cm−2, 0.5 mAh cm−2). Notably, at 1 mA cm−2 and 1 mAh cm−2, in the assembled Zn//Cu battery, the average CE reaches as high as 99 %. The Zn ion hybrid capacitor has excellent capacity retention and could stably cycle for 20,000 times (5 A g−1). The work proposes controlling the electrolyte as an effective method to develop stable AZBs.