Ice-templated Porous LiFePO4 Cathodes for High Performance Lithium Ion batteries

Abstract

In lithium ion batteries, introduction of porous structure has attracted considerable attention because of its advantages such as large surface area, good accessibility of the electrolyte, and high rate capability. Specifically, porous electrode can deliver lithium ion faster by reducing diffusion length. Then, the increased ion delivery can improve high rate performance of the batteries. In this study, we have prepared hierarchically porous LiFePO4 structure as a cathode electrode by an Ice-templating method. The structure is composed of hierarchical pore structures with macroscopically aligned thin pore channels and small voids created by packing of particles. The lamellar structured thin pore channels were tunable with parameter variations. The ice-templated LiFePO4 electrode was characterized by an X-ray diffraction (XRD) and elemental analysis, also scanning electron microscopy (SEM) and X-ray tomography were performed for structural analysis. Electrochemical performance as a function of electrode parameters, characterized by discharge capacity vs. discharge rate, conformed to improved rate capability, and also the structural stability was proven with the cyclic stability of the ice-templated porous electrode.