PVDF-based electrolyte decorated by Li29Zr9Nb3O40 Li-ion conductor and electrochemical performance of related solid-state batteries

Abstract

Solid-state Li-ion batteries (LIBs) have recently attracted much attention for their high safety and energy density. Polyvinylidene fluoride (PVDF) is as a potential electrolyte for solid-state LIBs due to its high permittivity, wide voltage window and excellent thermal stability. Here, Y3+-doped Li29Zr9Nb3O40 (LZNO) Li-ionic conductor with room temperature conductivity (σ25) of 1.26 × 10−4 S cm−1 is prepared. LZNO decorated PVDF-based composite solid electrolytes (CSEs) are fabricated. The PVDF-based CSE with 10% (mass ratio) of LZNO shows σ25 of 2.34 × 10−4 S cm−1, and has thermal stability with melting temperature up to 332 °C and voltage window of 4.8 V. The assembled Li(Ni0.8Co0.1Mn0.1)O2|CSE|Li cells show initial specific discharge capacity of 216.7 mAh g−1 at 0.1 C, and exhibit high capacity and cycle performance. LiFePO4|CSE|Li cells display initial specific discharge capacity of 137.4 mAh g−1 at 0.5 C and high cycle performance. Addition of LZNO powder in CSEs can inhibit the dehydrofluorination of PVDF during the charge-discharge of cells, alleviate the deterioration of interface resistance, and greatly improve the specific discharge capacity of cells at high rates.