Polymeric Ionic Liquid Gel Electrolyte for Room Temperature Lithium Battery Applications
By Safa, Meer; Chamaani, Amir; Chawla, Neha; El-Zahab, Bilal
Published in Electrochimica Acta
2016
Abstract
Abstract Free-standing gel polymer electrolytes (GPE) composed of the polymeric ionic liquid poly[diallyldimethylammonium] bis(trifluoromethane) sulfonimide, the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethane) sulfonimide, and lithium salt are reported for their use in lithium batteries. The {GPEs} are thermally stable and contain ionic liquid and salt contents of up to 80 wt.% which results in highly ionically conductive electrolyte films with ? = 3.35 mS cm?1. The affinity of the polymeric ionic liquid with the ionic liquid and salt components of the {GPE} allows wide electrochemical stability window ?0.1-4.9 V and increased lithium ion transference number. In addition, the {GPEs} suppressed dendrite formation compared to ionic liquid electrolytes and in turn enabled the use of these {GPEs} in batteries with lithium anodes. Galvanostatic charge/discharge cycling of Li/GPE/LiFePO4 cells shows discharge capacity of 169.3 mAh g?1 at C/10, 126.8 mAh g?1 at 1C, and impressive capacity retention capability for 40 cycles at up to 5C rate, at 22