Improving thermal stability and electrochemical performance of polymer solid electrolyte membranes with a novel TiO2@PA-APP composite additive

Polymer solid electrolytes (PSEs) are still under the safety risk because of flammability and low mechanical strength. Here a TiO 2 coated piperazine-modified ammonium polyphosphate (TiO 2 @PA-APP) is synthesized and incorporated into poly (ethylene oxide) (PEO)-based PSE membranes to meet the above challenges. The thermal stability and ionic conductivity of PSE membrane incorporated with TiO 2 @PA-APP have been improved. Micro-scale combustion calorimetry experiments indicate a dramatic 70 % decrease in heat release rate, from 919 W g −1 to 267 W g −1 . The lithium symmetric cell demonstrates remarkable durability, operating normally for 500 h with minimal polarization potential across various current densities at 60 °C. The all solid-state LiFePO 4 //Li battery using the cathode-supported TiO 2 @PA-APP/PEO-PSE membrane can reach a high discharge specific capacity of 153 mAh g −1 at 0.1 C and demonstrates good cycle performance, achieving a capacity retention rate of 88 % after 200 cycles at 0.2 C, along with an average coulombic efficiency of 99.24 %. These findings underscore the effectiveness of the TiO 2 @PA-APP flame retardant in fabricating solid-state lithium-ion batteries that provide enhanced safety and exceptional electrochemical performance.