Graphdiyne oxide in polymer electrolytes: Synergistic non-covalent interactions boosting Li-ion transport and LiF-rich solid electrolyte interface

Abstract

Solid-state polymer electrolytes (SPEs) face challenges including low lithium-ion transference numbers (t_Li⁺) and uncontrolled lithium dendrite growth. Herein, a design concept for the synergic regulation of the non-covalent interactions within SPEs is proposed. Graphdiyne oxide (GDYO), featuring abundant carboxyl groups, is incorporated into polyethylene oxide (PEO)-based SPEs. GDYO engages in hydrogen bonding with PEO and electrostatic interactions with LiTFSI, facilitating the transfer of Li⁺ in SPEs. Furthermore, a LiF-rich solid electrolyte interphase (SEI) is formed, effectively suppressing dendrite formation. The optimized GDYO/PEO SPE achieves a high t_Li⁺ of 0.75 and stable Li plating/stripping over 1300 h in Li||Li symmetric cells. GDYO/PEO SPE enables coin full cells to exhibit superior cycling stability, rate performance, and high-voltage suitability, while also offering superior safety and flexibility for pouch cells. Our results highlight the pivotal role of synergistic non-covalent interactions in SPEs, providing a novel strategy for improving the performance of energy storage batteries.