Electric Potential Mapping Measurement for All-Solid-State Lithium-Ion Batteries using a Terahertz Chemical Microscope

Terahertz Chemical Microscope (TCM) has been developed to measure the electric potential distribution of batteries during charging and discharging. The battery is mounted on a sensing plate with SiO2 and Si films on a sapphire substrate and irradiate with a femtosecond laser to generate THz pulses. THz amplitude is proportional to the electric potential on the sensing plate, so the electric potential distribution of the battery on the sensing plate can be measured. In this study, a method was developed to measure the cathode surface of an all-solid-state lithium ion battery by the TCM and visualized the electric potential distribution of the battery. This result shows that the TCM could be a useful tool for measuring of all-solid-state batteries.