A concentrated poly(ethylene carbonate)/poly(trimethylene carbonate) blend electrolyte for all-solid-state Li battery

Electrochemical and ion-transport properties of polymer blend electrolytes comprising poly(ethylene carbonate) (PEC), poly(trimethylene carbonate) (PTMC) and lithium bis(fluorosulfonyl) imide (LiFSI) were studied in this work, and the electrolyte with the best blend composition was applied in all-solid-state Li batteries. The ionic conductivity of both PEC and PTMC single-polymer electrolytes increased with increasing Li salt concentration. All PEC and PTMC blend electrolytes show ionic conductivities on the order of 10？5？S？cm？1 at 50？°C, and the ionic conductivities increase slightly with increasing PEC contents. The PEC6PTMC4-LiFSI 150？mol% electrolyte demonstrated better Li/electrolyte electrochemical and interfacial stability than that of PEC and PTMC single-polymer electrolytes and maintained a polarization as low as 5？mV for up to 200？h during Li metal plating and stripping. A Li|SPE|LFP cell with the PEC6PTMC4-LiFSI 150？mol% electrolyte exhibited reversible charge/discharge capacities close to 150？mAh？g？1 at 50？°C and a C/10 rate, which is 88% of the theoretical value (170？mAh？g？1)