Enhanced Electrochemical Properties of LiFePO4 Electrodes with Carboxylated Poly(vinyl difluoride) in Lithium-Ion Batteries: Experimental and Theoretical Analysis

Abstract

The adhesion strengths between LiFePO4 cathodes and aluminum (Al) current collectors as well as the corresponding electrochemical properties of electrodes with carboxylated poly(vinyl difluoride) (C-PVdF) were experimentally and theoretically investigated. The adhesion strength of LiFePO4 cathodes with C-PVdF on Al current collectors were increased, compared with that of as received PVdF, resulting in the reduction of the internal resistance of the electrode. These results were supported by theoretical simulations based on the Metropolis Monte Carlo method. Electrochemical experiments indicated that the cyclability and rate capabilities of the cathode were improved as the weight fraction of C-PVdF in the electrode increased up to 70% of the polymer binders. In addition, 18 650-sized full cells employing the electrodes with C-PVdF showed promising performance in terms of rate capability as well as long-term cyclability, which suggests that this strategy can be beneficial for the realization of high power sources such as electric Vehicle's, electric bikes, and various power tools.