# A Homogeneous Hexagonal-Structured Polymer Electrolyte Framework for High-Performance Polymer-Based Lithium Batteries Applicable at Room Temperature

## TL;DR

A new polymer electrolyte framework improves lithium battery performance at room temperature by enhancing ionic conductivity and stability.

## Contribution

A novel hexagonal-structured single-ion conducting gel polymer electrolyte is introduced for efficient room-temperature lithium batteries.

## Key findings

- The h-SICGPE achieves ionic conductivity of 2.46 mS cm−1 at room temperature.
- The electrolyte shows oxidative stability up to 4.9 V and 97.65% coulombic efficiency.
- Capacity retention of 88.3% is achieved, confirming its effectiveness for polymer-based batteries.

## Abstract

In polymer-based lithium batteries, polymer electrolytes (PEs) exhibit limited ionic conductivity at room temperature (25 °C). To address this issue, this paper describes a hexagonal-structure-based single-ion conducting gel polymer electrolyte (h-SICGPE) framework with a robust and efficient cross-linked polymer network, applicable to polymer-based batteries even at 25 °C. The proposed cross-linked polymer network backbone of the h-SICGPE, as a semisolid-state thin film type, has the homogeneous honeycomb structure incorporating anion receptor(s) inside each of its hexagonal closed cells and is obtained by cross-linking between trimethylolpropane tris(3-mercaptopropionate) and poly(ethylene glycol) diacrylate in a newly synthesized anion–receptor solution. The excellent structural capability of the h-SICGPE incorporating Li+/TFSI− can enhance ionic conductivity and electrochemical stability by suppressing crystallinity and expanding free volume. Further, the anion receptor in its free volume helps to effectively increase the lithium-ion transference number by immobilizing counter-anions. Experimental results demonstrate dramatically superior performance at 25 °C, such as ionic conductivity (2.46 mS cm−1), oxidative stability (4.9 V vs. Li/Li+), coulombic efficiency (97.65%), and capacity retention (88.3%). These results confirm the developed h-SICGPE as a promising polymer electrolyte for high-performance polymer-based lithium batteries operable at 25 °C.