리튬 치환된 바인더 적용 리튬이차전지의 전기화학적 특성에 관한 연구

Abstract

The polymeric binders are closely related to the controlling volume expansion of active materials, the adhesion strength of active materials on current collector, and a mechanical property of the electrodes. In this study, the electrochemical properties for aqueous anode of lithium ion batteries (LIBs) are investigated by applying the modified polymeric binders. For the first aqueous anode, Li-PAA is synthesized from PAA and applied to Si-metal alloy-based negative electrode. Its mechanical and electrochemical properties are enhanced due to the control of volume expansion and improved lithium ion kinetics caused by the modification of polymeric binder. For the second aqueous anode, it is investigated that the physicochemical properties and electrochemical behaviors of graphite-based negative electrode by employing Li-CMC substituted from Na-CMC. For thick graphite electrode prepared with Li-CMC, initial capacity and cycle life are increased owing to the increased lithium ion kinetics. However, the adhesion strength of active materials on current collector is decreased. To alleviate this drawback, mixture binder systems with Na-CMC relating with adhesion force are designed and its electrochemical behaviors are conducted based on optimum condition of binder system. Additionally, the electrochemical properties for non-aqueous cathode of LIBs are investigated. The theoretical and experimental investigations of LiFePO4 cathode are conducted based on mixture binder system of PVdF and carboxylated PVdF (c-PVdF). The adhesion strength and electrochemical properties are improved as the ratio of c-PVdF is 70 % in mixture binder system.