Molecularly Crowding Electrolytes and Tailored Electrodes for High-performance Aqueous Mn-Ion Hybrid Micro-supercapacitors

Abstract

Aqueous Mn−ion hybrid micro−supercapacitors (AMIHMSCs) are promising systems, which can greatly improve the energy density and power density of traditional aqueous micro supercapacitors. Unfortunately, the development of AMIHMSCs has been challenging due to the low redox potential and high chemical activity of Mn metal, as well as the low capacity and poor cycle life of electrode material resulting from Mn²⁺ with high charge density and large solvated ion radius. Herein, we report the first generation AMIHMSCs assembled with molecular crowding electrolytes, hydroxylated Ti₃C₂T_x MXene (H−Ti₃C₂ MXene) anode and Al_xV₂O₅ with dimethyl formamide molecules intercalation (AlVO−DMF) cathode. Benefiting from the wide electrochemical stability window and unique Mn²⁺ solvation structure in molecular crowding electrolytes, excellent capacitance of H−Ti₃C₂ MXene and enhanced structural stability of AlVO−DMF, the AMIHMSCs exhibit high energy density, power density and long cycle life. This work provides a pathway for designing high−performance AMIHMSCs.