Nonionic Surfactant Coconut Diethanol Amide Inhibits the Growth of Zinc Dendrites for More Stable Zinc-Ion Batteries

Uncontrollable growth of zinc dendrites and byproducts has become the main factor which limits the life of zinc-ion batteries. Herein, we reported a nonionic surfactant, coconut diethanolamide (CDA), which can be applied as an electrolyte additive. It not only effectively suppresses zinc graft growth and promotes uniform growth of zinc dendrites but also efficiently inhibits the generation of side reactions and byproducts. When CDA is added to the electrolyte, the life of the battery has been significantly improved (1580 h). Compared with an electrolyte without CDA (100 h), its life has grown more than 10 times. CDA can adsorb on the surface of the zinc electrode to form a protective layer by its special molecular structure. Therefore, zinc ions will have a higher barrier for deposition, and there should be induced uniform deposition. Moreover, the Cu/Zn cell shows 98% average Coulomb efficiency in the electrolyte with CDA after about 620 h. In addition, after long-term cycles, the addition of CDA enables the MnO2/Zn cell to show 85% capacity retention and 98% average Coulomb efficiency. The electrolyte additives reported in this study will provide a more convenient and environmentally friendly way to effectively solve the problem of zinc branches.