A high-voltage poly(methylethyl α-cyanoacrylate) composite polymer electrolyte for 5 V lithium batteries

Abstract

High-voltage lithium batteries have attracted increasing attention for large scale energy storage application in electric vehicles, smart grids and other electronic devices. However, a major bottleneck to achieve high-voltage lithium batteries is the anodic voltage stability of electrolytes. Herein, we fabricate a composite polymer electrolyte, comprised of poly(methylethyl α-cyanoacrylate), nonwoven polytetrafluoroethylene and lithium bis(oxalate)borate salt. The composite polymer electrolyte presents a wide electrochemical window, which is explored to address the above-mentioned bottleneck. It is demonstrated that such a composite polymer electrolyte exhibits a higher ionic conductivity (1.24 mS cm⁻¹ at 25 °C), better dimensional thermal resistance (150 °C) and higher ion transference number (0.63) compared to those of commercially available liquid electrolytes with a polypropylene separator. In addition, LiNi_0.5Mn_1.5O₄/Li batteries employing such a composite polymer electrolyte deliver excellent cycling performance and outstanding rate capability. So, it is demonstrated that the poly(methylethyl α-cyanoacrylate) based polymer electrolyte appears to be a promising candidate of high-voltage lithium battery electrolyte towards next generation high energy density batteries.