All-solid-state lithium batteries with Li3PS4 glass as active material

Abstract

For increasing energy densities of all-solid-state cells, utilizing solid electrolytes in the electrode layer as an active material is useful. Favorable electron conduction paths to the Li3PS4 glass electrolyte were formed by mechanical milling with AB as the conductive additives. The all-solid-state cells with Li3PS4 glass only or mixture prepared by grinding the Li3PS4 glass and AB as a positive electrode did not work. On the other hand, the cell with Li3PS4-AB composite electrodes prepared by milling was successfully charged and then discharged. Initial charge capacity of the cell with the Li3PS4-AB composite electrode was 220 mAh g−1 at 0.064 mA cm−2. Open circuit voltage of the cell was 2.6 V vs. Li, which was higher than that with Li2S active material. In the cell with the Li2S–Li3PS4-AB composite electrode, the Li3PS4 glass functioned as not only Li+ ion conductive paths to Li2S but also active material itself, suggesting that the use of the solid electrolytes as active materials in electrode layers is useful for increasing reversible capacity per gram of a positive electrode.