The suppression of lithium dendrites by a triazine-based porous organic polymer-laden PEO-based electrolyte and its application for all-solid-state lithium batteries

Abstract

A triazene-p-phenylenediamine-based porous organic polymer (TP-POP) was successfully synthesized and incorporated as a filler in the PEO + LiTFSI matrix. The composite polymer electrolyte (CPE) membranes were characterized via SEM, DSC, TGA and tensile studies. Their electrochemical properties including ionic conductivity and compatibility and dendrite features were also investigated. The ionic conductivity increased by one order magnitude upon the addition of 2 wt% of TP-POP in the polymeric matrix, which was attributed to the formation of a transition Lewis acid–base-type of interaction for Li⁺-ion hopping. The CPE comprising PEO + LiTFSI + TP-POP exhibited not only higher thermal stability and better interfacial properties but also prevented dendrite growth even after 140 h. Finally, a 2032-type coin cell composed of LiFePO₄/CPE/Li was assembled and its cycling performance was analysed for different C rates at 60 °C. Stable cycling was achieved even at the rate of 1C.