A New (De)Intercalation MXene/Bi Cathode for Ultrastable Aqueous Zinc-Ion Battery

The emerging aqueous zinc-ion batteries (ZIBs) have received extensive attention and research due to their unique advantages of low cost, safety, and environmental friendliness. However, the development of appropriate cathode materials to improve battery performance remains a major challenge. Herein, a new MXene and Bi (MXene/Bi) composite material is first applied as the (de)intercalation cathode of ZIB. The dispersed MXene nanosheets in the composite materials greatly improve the conductivity and hydrophilicity of the electrode, and prevent the stacking and the volume expansion in the charge/discharge process of 2D Bi fragments. The experimental results show that composite MXene/Bi electrode has remarkable capacity and ultralong life. Next, the good kinetics and (de)intercalation energy storage mechanism of ZIB are revealed through abundant electrochemical tests and ex situ characterization. The quasi-solid-state (QSS) ZIB is also constructed, showing superior electrochemical performance, flexibility, pressure resistance, and heat resistance. Besides, the QSS ZIB can be used directly as a self-powered pressure sensor to monitor the external pressure in real time based on the response current. This study not only demonstrates that MXene/Bi is a potential cathode for ZIBs, but also offers a feasible path to explore and design the next generation of high-performance multifunctional ZIBs.