Plastic Crystal Polymer Electrolytes with Anion-Trapping Boron Moieties for Room Temperature All-Solid-State Sodium Batteries

Abstract

Sodium-ion batteries (SIBs) have been considered as promising alternatives to lithium-ion batteries (LIBs) particularly in large scale electric energy storage applications for renewable energy and grid due to low cost and the huge abundance of sodium resources. However, increasing safety issues caused by the use of conventional organic liquid electrolytes (LEs) greatly hinder the commercial application of SIBs in electric vehicles or hybrid electric vehicles [1]. Replacing LEs with solid electrolytes (SEs) can inherently address such safety problems. However, it is a compelling challenge to develop SEs with superior room-temperature ionic conductivity, high ion transference number, considerable mechanical property, and low electrolyte/electrode interfacial resistance [2]. Recently, we developed a new type of nonwoven supported plastic crystal polymer electrolyte containing anion-trapping boron moieties (B-PCPE), which prepared by in situ growth method using UV-curing technique. In addition, the plastic crystal electrolyte modified electrodes were also designed to reduce interfacial resistance. The B-PCPE shows excellent room temperature ionic conductivity (0.36 mS/cm) and greatly enhanced sodium transference number (0.62) due to the presence of anion-trapping boron moieties. All-solid-state SIB assembled using the B-PCPE with anion acceptor exhibits excellent cycle performance and rate capability at room temperature. The cell delivers first discharge capacity of 104.8 mAh/g with Coulombic efficiency of 94.1% and the capacity retention is about 80.1% after 120 cycles at 0.1 C. We believe this B-PCPE is a promising candidate for practical application and our work provides a new perspective to design high-performance solid electrolyte for ambient-temperature all-solid-state batteries with exceptional rate capability and cycle stability.