Self‐Healing Polymer Electrolyte for Dendrite‐Free Li Metal Batteries with Ultra‐High‐Voltage Ni‐Rich Layered Cathodes
Zhuo Li, Jialong Fu, Sheng Qiang Zheng, Dinggen Li, Xin Guo
Abstract
Abstract Practical applications of polymer electrolytes in lithium (Li) metal batteries with high‐voltage Ni‐rich cathodes have been hindered by the dendrite growth and poor oxidative stability of electrolytes. Herein, a self‐healing polymer electrolyte is developed by in situ copolymerization of 2‐(3‐(6‐methyl4‐oxo‐1,4‐dihydropyrimidin‐2‐yl)ureido)ethyl methacrylate (UPyMA) and ethylene glycol methyl ether acrylate (EGMEA) monomers. With the electrolyte, the dendrite growth is inhibited by spontaneously repairing dendrite‐induced defects, cracks, and voids at the Li/electrolyte interface; the suppressed dendrite growth and associated electro‐chemo behaviors are visualized by the kinetic Mont‐Carlo simulation. Benefitting from the high ionic conductivity, wide electrochemical window and good interfacial stability, the self‐healing polymer electrolyte enables stable cycling of the LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) cathode under 4.7 V, achieving a high specific capacity of ≈228.8 mAh g −1 and capacity retention of 80.4% over 500 cycles. The new electrolyte is very promising for developing highly safe and dendrite‐free Li metal batteries with high energy density.