A Tape-Casting/Freeze-Drying Approach to Prepare Low-Tortuous Graphite Electrodes

Abstract

Lithium ion batteries (LIBs) with high energy density and fast charging capability are in high demand to satisfy the development of plug-in hybrid electric vehicle (PHEV) and full electric vehicle (EV). Limited ion transport in thick electrodes is one of the major challenges that impede the rate capability of a battery. Directional freeze-drying, with the aid of ice templating, is a feasible method to introduce low-tortuous pore structure in composite electrodes. In this study, we propose a traditional tape-casting process followed by the directional freeze-drying and calendering procedures to prepare graphite electrodes with low tortuosity. Compared with the traditional tape-casting method, the tortuosity of the graphite electrodes is effectively reduced by the subsequent freeze-drying process. Higher capacity retention and better rate capability are achieved due to enhanced ion transport capability in the low-tortuous microstructure. We confirmed that the concept of continuous tape-casting/freeze-drying is an effective and scalable approach for manufacturing high-performance thick battery electrodes.