Enhancing rate capability of graphite anodes for lithium-ion batteries by pore-structuring

Abstract

For the development of high-performance lithium-ion batteries (LIBs), numerous studies on 3-dimensionalized electrode structures have been conducted to improve the ionic diffusion, rate performance, and electrolyte wetting ability. Due to the decrease in ionic polarization, structured electrodes show much higher capacity retention compared to typical electrodes, especially at high current rates. In this study, pore-structured graphite (Gr) electrodes were synthesized using pore-formation agent particles (polytetrafluoroethylene (PTFE)), which possess a unique thermal unzipping property. After the heat treatment, the PTFE particles were depolymerized to form micro-sized pores. The effect of the 3-dimensionalized electrode structure on the electrochemical properties was investigated in detail. As a result, it was observed that the rate capability and cycle life of pore-structured Gr electrodes enhanced owing to their improved physical properties, such as wetting ability and shortened ionic diffusion pathways. Because our approach does not require changes in the existing electrode chemistry and slurry process, it is one of the most cost-effective and applicable ways to improve fast charging capability.