Exploring High Li<sup>+</sup> Transference Number Solid-State Electrolytes Based on a Poly(ε-caprolactone) Polymer Matrix with Efficient Lithium Salt Dissociation for Applications in Lithium-Metal Batteries
Aolai Wang, Dexuan Pei, Ziying Liu, Shuo Huang, Guozhong Cao, Hongyun Jin, Shuen Hou
Abstract
Composite polymer electrolytes (CPEs) with high security and mechanical flexibility are needed for all-solid-state lithium-metal batteries (LMBs). However, their practical application is hindered by the increasing demand for high-power and high-areal-energy-density storage solutions. Herein, a high-powered CPE relying on poly(ε-caprolactone) (PCL) as the polymer matrix is developed. The binding energy of Li + -PCL is predicted to be −130.163 kcal·mol –1 via density functional theory calculations, which implies a high dissociation of Li salts in the PCL matrix. The weak interactions between the Li + and the polymer chains enable the CPEs with a high Li + transfer number ( t Li+ ) of 0.71. Besides, LiFePO 4 //Li batteries deliver a high capacity retention of 85% for over 600 cycles at 2.0C. This work demonstrates the tremendous potential of PCL-based CPEs in promoting the application of high-power-performance LMBs.