A Dual‐Functional Organic Electrolyte Additive with Regulating Suitable Overpotential for Building Highly Reversible Aqueous Zinc Ion Batteries

Abstract Aqueous zinc ion batteries (AZIBs) with high safety, low cost, and eco‐friendliness advantages show great potential in large‐scale energy storage systems. However, their practical application is hindered by low Columbic efficiency and unstable zinc anode resulting from the side reactions and deterioration of zinc dendrites. Herein, tripropylene glycol (TG) is chosen as a dual‐functional organic electrolyte additive to improve the reversibility of AZIBs significantly. Importantly, ab initio molecular dynamics theoretical simulations and experiments such as in situ electrochemical impedance spectroscopy, and synchrotron radiation‐based in situ Fourier transform infrared spectroscopy confirm that TG participates in the solvation sheath of Zn 2+ , regulating overpotential and inhibiting side reactions; meanwhile, TG inhibits the deterioration of dendrites and modifies the direction of zinc deposition by constructing an adsorbed layer on the zinc anode. Consequently, a Zn‐MnO 2 full cell with TG electrolyte exhibited a specific capacity of 124.48 mAh g ‐1 after 1000 cycles at a current density of 4 A g ‐1 . This quantitative regulation for suitable solvation sheath and adsorbed layer on zinc anode, and its easy scalability of the process can be of immediate benefit for the dendrite‐free, high‐performance, and low‐cost energy storage systems.