Novel Single-Ion Conducting Gel Polymer Electrolyte with Honeycomb-Like Morphology Prepared Using Brush Copolymer for Lithium-Ion Battery Application

Abstract

In this work, a facile and accurate method is reported for the delocalization of negative charge on fluorinated polymers to obtain high-performance single-ion conducting polymer electrolytes (SICPs) based on brush copolymers with simultaneous high ionic conductivity and t Li+ . The poly(styrene sulfonate) (PSSA) single ion-conducting moieties were grafted-from C–F linkages to the fluorinated polymer’s backbone via the atom transfer radical polymerization method. The chemical structure characterization of the synthesized brush copolymers via 1 H-NMR and thermal gravimetric analyses (TGA) confirmed 25% grafting of PSSA to the poly(vinylidene fluoride) backbone. In continue, the pristine and single-ion fluorinated polymer membranes with bi-continuous honeycomb-like morphology structures were prepared via the vapor-induced phase inversion (VIPS) method. After immersing in a liquid electrolyte, the prepared SICP demonstrated promising ionic conductivity ( σ ), t Li+ , and electrochemical stability of 1.9 × 10 −3 Scm −1 , 0.82, and 5.2 V (vs Li + /Li), respectively. The assembled Li/SICP/LiMn 2 O 4 half-cells revealed an improved discharge capacity of 168 mA hg −1 at 0.1C. The charge-discharge studies revealed that the ohmic-resistance and polarization resistance of fluorinated polymer electrolytes could be decreased by the effect of PSSA-grafted moieties. The results of this work confirmed the promising capability of these new SICPs for high-safety LIBs.