A Non-Flammable Zwitterionic Ionic Liquid/Ethylene Carbonate Mixed Electrolyte for Lithium-Ion Battery with Enhanced Safety.

Zeliang Guan,Zhangquan Peng,Zhijun Zhang,Binyang Du

doi:10.3390/ma14154225

Abstract

Today, the requirement for clean, highly efficient, and safe energy seems to be higher and higher due to non-renewable energy and pollution of the environment. At this moment, lithium-ion batteries (LIBs) look like a reliable solution for this dilemma since they have huge energy density. However, the flammability of the conventional electrolyte used in the LIBs is one of critical disadvantages of LIBs, which compromises the safety issue of LIBs. Herein, we reported a non-flammable zwitterionic ionic liquid-based electrolyte named TLPEC, which was fabricated by simply mixing a novel zwitterionic ionic liquid TLP (93 wt%) and ethylene carbonate (EC, 7 wt%). The TLPEC electrolyte exhibited a wide electrochemical potential window of 1.65–5.10 V and a robust ionic conductivity of 1.0 × 10−3 S cm−1 at 20 °C, which renders TLPEC to be a suitable electrolyte for LIBs with enhanced safety performance. The LIBs, with TLPEC as the electrolyte, exhibited an excellent performance in terms of excellent rate capability, cycling stability, and high specific capacity at 25 and 60 °C, which were attributed to the stability and high ionic conductivity of TLPEC electrolyte during cycling as well as the excellent interface compatibility of TLPEC electrolyte with lithium anode.

Highlights

Published: 28 July 2021Lithium-ion batteries (LIBs) have attracted extensive attention because of the urge for clean energy and less pollution to the environment
Organic solvents such as propylene carbonate (PC), dimethyl carbonate (DMC), 1, 2-dimethoxyethane (DME), and tetraethylene glycol dimethylether (TEGDME) are widely used as electrolytes for lithiumion batteries (LIBs) because of their low melting points, high ionic conductivities, and low costs [6,7]. These above-mentioned common electrolytes have some disadvantages, such as low flashing point and flammability, which will lead to fire if local overheating in LIBs is encountered
The low Tg and high decomposition temperature of TLP indicate that TLP can be potentially used as an electrolyte component for LIBs

Summary

Introduction

Published: 28 July 2021Lithium-ion batteries (LIBs) have attracted extensive attention because of the urge for clean energy and less pollution to the environment. LiFePO4 (LFP) is used as cathode material of LIBs, which can provide a theoretical charge capacity of 170 mAh g−1 for LIBs [1,2], and has the advantages of high temperature stability, environmental friendliness, and rich resources [3,4,5]. Organic solvents such as propylene carbonate (PC), dimethyl carbonate (DMC), 1, 2-dimethoxyethane (DME), and tetraethylene glycol dimethylether (TEGDME) are widely used as electrolytes for LIBs because of their low melting points, high ionic conductivities, and low costs [6,7]. To develop new kinds of electrolytes that are nonflammable and exhibit excellent electrochemical properties is an important task that has attracted extensive investigations in the scientific community

Methods

Results

Conclusion