Understanding the Electrochemical Performance of Spongy C–F Derivative Chains as an Effective Anion Trapping Composite Matrix for Li-Ion Batteries

Recently, the rapid growth of Li-ion battery (LIB) technologies requires the exploit of highly porous, thermally, and electrochemically stable composite polymer electrolyte (CPE) membranes. Herein, a novel spongy asymmetric composite matrix composed of poly(vinylidene fluoride cohexafluoropropylene), cellulose, and boron nitride was designed via a spinning cum immersion precipitation route. Notably, the fabricated PCBN-CPE membrane displays a high surface porosity, good electrolyte uptake, better mechanical stability, and excellent thermal stability. The fabricated membrane, assembled with a LiFePO4∥Li electrochemical cell, exhibits splendid cycling stability, with a primary specific discharge capacity of 154.1 mAh g–1 and a capacity retention of 73.8% after 250 cycles at 0.2 C. In addition, the composite polymer electrolyte renders an excellent Li-ion transference number (0.86) at room temperature. Interestingly, the density functional results elucidate that the existence of boron nitrides on the porous matrix can effectively trap anions (PF6–) and, thereby, reduce the growth of Li dendrites. Therefore, the present work affords a fabulous approach for high-performance Li-ion battery (LIB) application.