Study of Li Pre-dope to the Negative Electrode of a Lithium-ion Capacitor and a Lithium-ion Battery Using 8-Reference Electrodes

Abstract

Lithium ion pre-doping phenomena of lithium ion capacitor (LIC) and lithium ion battery (LIB) were studied using eight reference electrodes embedded around a negative electrode and a lithium metal electrode. The lithium metal electrode was set in the neighbor of the carbonaceous negative electrode. The negative electrode and the lithium metal electrode were short-circuited, and electric current was measured by using an ammeter. Just after the connection of the negative electrode and the lithium metal electrode, rushed current was observed and it was decreased gradually. The potentials of the negative electrode were decreased gradually from near the lithium metal electrode to the end of the negative electrode. However, the potentials in the horizontal plane of the negative electrode did not become uniform even after 60 hours. Slight electric current between the negative electrode and the lithium metal electrode also was observed even after 60 hours. Potential difference between the lithium metal electrode and the negative electrode becomes the biggest driving force. Temperature becomes an acceleration factor. Great difference was not observed between LIC and LIB in the pre-doping phenomena at 60°C.