Improvement of cycle performance of all-solid-state lithium ion batteries with clustered composite electrodes using PTFE powder

Abstract

Cycle performance is a technical challenge for the all-solid-state lithium ion battery because of contact loss between the active materials and solid electrolytes. Providing an intimate adhesive contact between solid electrolyte and active materials might be the most effective and practical solution. To address this issue, we added PTFE powder to the composite cathode in order to create good conducting paths for Li ions and electrons of the lithium batteries. We show the PTFE added composite cathode has significantly better cycle performance. Electrochemical impedance spectroscopy suggests that the charge transfer resistance increased as the amount of PTFE powder increased. On the other hand, differential capacity vs. voltage profiles showed that polarization of the composite cathode was suppressed as cycle number increased in the PTFE added composites. A preliminary model is suggested to guide future development of the microstructure in all-solid-state batteries.