Mechanically robust epoxy resin-based gel polymer electrolyte stabilizing ion deposition for high-performance lithium metal batteries

Lithium metal batteries (LMBs) with extremely excellent energy density exhibit highly potential for future power applications. However, due to the dendrite growth caused by the strong activity of lithium metal, severe safety concerns and low life range are still great challenges for LMBs. Herein, a porous epoxy resin-based gel polymer electrolyte (PEE) with a special structure of the skeletal network fully filled with epoxy resin globules is developed. The PEE membranes with abundant communicating pores channels and rich polar groups (-OH, C-O-C) show high lithium ion conductivity and robust mechanical performance (the Young's modulus of 312 MPa after activation by liquid electrolyte) as well as superior thermal stability (no dimensional change at 250 C). Furthermore, the typical PEE-2.75 membrane can restrain lithium dendrites growth effectively and stabilize lithium ion deposition (over 1000 h of stable operation at 2 mA cm(-2)). Therefore, the full cell Li//PEE-2.75//LiFePO4 shows a significant rate capacity of 92.8 mA h g-1 at 5 C and stable cycle performance (capacity maintained at over 82.33% after 195 cycles at 1 C). This work presents a simple and effective way for the application of epoxy resin in high-performance LMB.