Tween-20 induced self-healing deposition towards ultra-stable Zn electrode

Abstract

Zn-ion battery has revealed potential application in grid energy storage due to the high energy density, cost effectiveness and intrinsic safety. However, its large-scale application is hindered by the unstable Zn electrode caused by the continuous zinc dendrites growth. Herein, Tween-20 is selected as a functional additive of electrolyte to enhance the stability of Zn electrode through inducing self-healing Zn deposition. The Tween-20 molecules with rich carbonyl and ether groups preferentially adsorb on the top surface of vertically grown Zn nanosheets formed by initial corrosion, guiding the Zn deposition between them, and finally constructing smooth surface, demonstrating a self-healing feature. Simultaneously, the absorbed Tween-20 can prevent water molecules and SO42− from directly contacting the zinc surface, reducing the zinc corrosion and thus enhance the stability of Zn electrode. As a result, the Zn||Zn symmetric battery using the modified electrolyte with Tween-20 displays super long-lifespan of more than 6500 h at a current density of 1 mA cm−2 with a capacity of 0.5 mAh cm−2. Even in the practical applications, the electrolyte containing Tween-20 can also enable the Zn||MnO2 battery to cycle more than 2500 times almost without decay at 1.8 A g−1.