Phenylboronic Acid Functionalized Calix[4]pyrrole-Based Solid-State Supramolecular Electrolyte

Abstract

Solid-state polymer electrolytes (SPEs) suffer from the low ionic conductivity and poor capability of suppressing lithium (Li) dendrites, which limits their utility in the preparation of all solid-state Li-metal batteries (LMBs). It is reported here a flexible solid supramolecular electrolyte that incorporates a new anion capture agent, namely a phenylboronic acid functionalized calix[4]pyrrole (C4P), into a poly(ethylene oxide) (PEO) matrix. The resulting solid-state supramolecular electrolyte demonstrates high ionic conductivity (1.9 × 10^-3 S cm^-1 at 60 °C) and a high Li⁺ transference number ( $t_{{\mathrm{Li}}^{+}}$ = 0.70). Furthermore, the assembled Li|C4P-PEO-LiTFSI|LiFePO₄ cell allows for stable cycling over 1200 cycles at 1 C at 60 °C, as well as good rate performance. The favorable performance of the C4P-PEO-LiTFSI SPE leads to suggest it can prove useful in the creation of high energy density solid-state LMBs.

Keywords: calix[4]pyrrole; host-guest chemistry; lithium metal batteries; solid-state polymer electrolytes; supramolecular electrolyte.