Electrochemical Self‐Healing Nanocrystal Electrodes for Ultrastable Potassium‐Ion Storage

Abstract The unique properties of self‐healing materials hold great potential in battery systems, which can exhibit excellent deformability and return to its original shape after cycling. Herein, a Cu 3 BiS 3 anode material with self‐healing mechanisms is proposed for use in ultrastable potassium‐ion battery (PIB) and potassium‐ion hybrid capacitor (PIHC). Different from the binder design, Cu 3 BiS 3 anode can exhibit the dual advantages of phase and morphological reversibility, further remaining original property after potassiation/depotassiation and exhibiting ultrastable cycling performance. The reversible electrochemical reconstruction during the continuous charge/discharge processes is beneficial to maintain the structure and function of the material. Furthermore, the conversion reactions during the charge and discharge process produce two advantages: i) suppressing the shuttle effect due to the formation of the heterostructure interface between Cu (111) and Bi (012); ii) Cu can avoid the agglomeration of Bi nanoparticles (NPs), further improving the electrochemical performance and long‐cycle stability of the Cu 3 BiS 3 electrode. As a result, the Cu 3 BiS 3 electrode not only exhibits a long cycle life in half cells, but also 2000 cycles and 12000 cycles in PIB and PIHC full cells, respectively.