Low‐Cost Multi‐Function Electrolyte Additive Enabling Highly Stable Interfacial Chemical Environment for Highly Reversible Aqueous Zinc Ion Batteries

The practicality of aqueous zinc ion batteries (AZIBs) for large‐scale energy storage is hindered by challenges associated with zinc anodes. In this study, a low‐cost and multi‐function electrolyte additive, cetyltrimethyl ammonium bromide (CTAB), is presented to address these issues. CTAB adsorbs onto the zinc anode surface, regulating Zn2+ deposition orientation and inhibiting dendrite formation. It also modifies the solvation structure of Zn2+ to reduce water reactivity and minimize side reactions. Additionally, CTAB optimizes key physicochemical parameters of the electrolyte, enhancing the stability of the electrode/electrolyte interface and promoting reversibility in AZIBs. Theoretical simulations combined with operando synchrotron radiation‐based in situ Fourier transform infrared spectra and in situ electrochemical impedance spectra further confirm the modified Zn2+ coordination environment and the adsorption effect of CTAB cations at the anode/electrolyte interface. As a result, the assembled Zn‐MnO2 battery demonstrates a remarkable specific capacity of 126.56 mAh g−1 at a high current density of 4 A g−1 after 1000 cycles. This work highlights the potential of CTAB as a promising solution for improving the performance and practicality of AZIBs for large‐scale energy storage applications. Constructing the electrode‐electrolyte interface with a stable chemical environment is one of the key targets for exploiting the high‐safety, high‐performance, and long‐lifespan aqueous zinc ion batteries at a practical level. Herein, cetyltrimethyl ammonium bromide is reported as a multi‐function electrolyte additive to effectively inhibit the hydrogen evolution reaction and deterioration of dendrites for ultra‐highly reversible zinc plating/stripping.