Trace-MXene-induced electrolyte reconfiguration and interfacial regulation for high-performance aqueous zinc-ion batteries

A trace-MXene-induced dual-interfacial regulation mechanism is proposed and experimentally validated. The negatively charged MXene nanosheets spontaneously adsorb on both Zn anodes and MnO 2 cathodes, forming a dynamic protective layer that suppresses parasitic reactions and promotes uniform Zn deposition. • Synergistic electrolyte reconfiguration and desolvation optimization are achieved. Combined theoretical and experimental analyses reveal that acetate ions and MXene collaboratively optimize the Zn 2+ solvation structure, reduce the desolvation energy barrier, and facilitate preferential Zn deposition along the (100) crystal plane. • Exceptional electrochemical performance is demonstrated in both symmetric and full cells. The symmetric Zn cell exhibits ultra-stable cycling for 1200 h at 1 mA cm −2 , and the Zn//MnO 2 full cell delivers a high capacity of 346 mAh g −1 with 70% retention after 1500 cycles at 5 A g −1 . Aqueous zinc-ion batteries (AZIBs) are promising alternatives to lithium-ion batteries owing to their intrinsic safety, low cost, and environmental compatibility. However, uncontrolled dendrite growth, hydrogen evolution, and interfacial passivation of Zn anodes severely hinder their long-term cycling stability. Herein, we propose a cost-effective electrolyte engineering strategy by introducing trace amounts of Ti 3 C 2 T x MXene nanosheets into a low-concentration zinc acetate (Zn(Ac) 2 ) electrolyte. The negatively charged MXene nanosheets are electrostatically assembled onto both Zn anodes and MnO 2 cathodes, constructing a dynamic interfacial layer that simultaneously suppresses parasitic reactions and enhances Zn 2+ transport. Density functional theory and molecular dynamics simulations reveal that acetate ions and MXene synergistically optimize Zn 2+ solvation structures, reduce desolvation energy, and guide uniform Zn deposition along the (100) facet. Consequently, the symmetric Zn cell exhibits ultra-stable cycling for 1200 h at 1 mA cm −2 , while the Zn//MnO 2 full cell delivers a high capacity of 346 mAh g −1 at 0.2 A g −1 and retains 70% capacity after 1500 cycles at 5 A g −1 . This work demonstrates a mechanistically driven and economically viable route for constructing high-performance, long-life AZIBs through multifunctional MXene-electrolyte interactions.