Largely Promoted Mechano‐Electrochemical Coupling Properties of Solid Polymer Electrolytes by Introducing Hydrogen Bonds‐Rich Network

Abstract

AbstractSolid polymer electrolytes (SPEs) and their composites are the most promising spices to access the commercial application in all‐solid‐state lithium batteries, where definite requirements for SPEs should be satisfied including moderate mechanical strength, high Li‐ion conductivity, and stable electrode/electrolyte interface. Herein, polyurethane‐based polymer (PNPU) is designed to further construct the hybrid solid polymer electrolyte (named as PNPU‐PVDF‐HFP) with poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) for high energy density solid‐state lithium metal batteries. The theoretical calculation and characterization demonstrate that PNPU‐PVDF‐HFP SPEs still maintain the multiple hydrogen bonding modes of PNPU, which contributes a significantly improved mechanical properties of the polymer membrane with compact structure. Moreover, it is corroborated that PNPU is involved to form the double Li+ transport paths in the hybrid electrolyte, accelerating the migration of lithium ions. Therefore, PNPU‐PVDF‐HFP SPEs are achieved with suitable tensile strength of 5.16 MPa and high elongation of 140.8%, high ambient ionic conductivity of 4.13 × 10−4 S cm−1, excellent ductile, and stability on the interface of lithium metal anode. The Li/ LiFePO4 and Li/Li[Ni0.8Co0.1Mn0.1]O2 solid‐state batteries using PNPU‐PVDF‐HFP SPEs present a stable cycling performance at 30 °C. This study provides a feasible strategy to achieve mechano‐electrochemical coupling stable SPEs for solid‐state batteries.