Electrochemical Self-Healing Nanocrystal Electrodes for Ultrastable Potassium-Ion Storage.

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 BiS 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 BiS 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 BiS electrode. As a result, the Cu BiS 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.