Polyurethane-Based Elastomeric Polymer Electrolyte for Lithium Metal Polymer Cells with Enhanced Thermal Safety
Hyebeen Son, Hyun‐Sik Woo, Myung‐Soo Park, Ji Min, Dong‐Won Kim
Abstract
A large number of applications such as mobile electronics and electric vehicles requires rechargeable batteries with high energy density and enhanced safety. To achieve these goals, lithium metal batteries employing solid-state electrolytes have become common despite the safety concerns associated with lithium metal. Polymer electrolytes have been studied as a solution for enhancing the safety of lithium metal batteries because they are non-volatile, non-flammable, and suppress the growth of lithium dendrites. In this study, highly elastic polyurethane (PU)-based polymer electrolytes were prepared in the form of thin flexible films, and their electrochemical characteristics were investigated. To improve the ionic conductivity, non-volatile and non-flammable 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide was added as a plasticizing additive to the polymer electrolyte. The cell assembled using a Li anode, PU-based elastomeric polymer electrolyte and composite LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode exhibited stable cycling performance by suppressing the growth of lithium dendrites as well as maintaining good interfacial contacts between electrolyte and electrodes during repeated cycling.