An ultrathin poly (ether-acrylate) solid electrolyte for high- performance solid-state lithium batteries

摘要

Solid polymer electrolyte is expected to be widely used in solid-state lithium batteries due to its good mechanical manufacturability and low cost. But the low ion conductivity, poor interface compatibility hindering the development of solid-state batteries. In this work, a rigid-flexible ultrathin (similar to 13 mu m) poly (ether-acrylate) (PEA) solid electrolyte membrane was prepared by controlling the mutual penetration of porous skeleton and electrolyte. For comparison, a thick PEA membrane (similar to 30 mu m) was also provided. We found that the thicker PEA membrane exhibits a porous structure and rough surface due to the physical shrinkage of polymer, while the ultrathin PEA shows more compact and flexible. Structural advantages give it higher tensile strength (114.7 MPa), doubled ionic conductance (218 mS), and higher lithium ion migration number from 0.81 to 0.93. Meanwhile, better interface contact was also achieved due to the smoother surface of ultrathin PEA, which promotes the uniform distribution of charges and uniform SEI film on the surface of lithium anode, thus inhibits the growth of lithium dendrites. Due to the improvement of basic physical properties and good interface contact, the assembled NCM622/PEA/Li solid-state battery shows improved rate and cycle performances. High-performance solid-state lithium batteries is expected to developed according to this ultrathin solid electrolyte membrane.