Semi‐Interpenetrating Network‐Structured Single‐Ion Conduction Polymer Electrolyte for Lithium‐Ion Batteries

Abstract A novel quasi solid single‐ion polymer electrolyte with semi‐interpenetrating network (semi‐IPN) structure has been prepared. The lithium‐ion conduction membrane is composed of both the cross‐linked lithiated poly‐2‐acrylamido‐2‐methylpropane sulfonic acid (PAMPS‐Li) as a polyanionic single‐ion lithium salt source and the high molecular weight polyethylene oxide (PEO) as a polymer matrix, in which the two components show great compatibility due to the special semi‐IPN structure. For such quasi‐solid electrolyte system, we have particularly studied the crystallinity variety and ionic conductivity change with a series of polymer salt concentration. The results show that the electrolyte has an appropriate mechanical stability, minimal crystallinity, and acceptable ionic conductivity of 1.34×10 −5 S/cm at 60 °C. Furthermore, the lithium‐ion conduction membrane shows the lithium‐ion dominating conductive property and high transport number of 0.77. Moreover, the LiFePO 4 /Li batteries’ cycle results show a high discharge capacity of 140.0 mAh/g and a retention of 90.4 % after 100 cycles at the rate of 0.2 C.