Preparation of amorphous Li 4SiO 4–Li 3PO 4 thin films by pulsed laser deposition for all-solid-state lithium secondary batteries

Abstract

Amorphous thin film electrolytes in the system Li 4SiO 4–Li 3PO 4 were prepared by pulsed laser deposition (PLD). The ionic conductivity of the amorphous film at the composition 50Li 4SiO 4·50Li 3PO 4 (mol%) was 1.6 × 10 − 6 S cm − 1 at room temperature which is higher than the conductivities of Li 3PO 4 and Li 4SiO 4 films. The 50Li 4SiO 4·50Li 3PO 4 film was coated on LiCoO 2 active material particles by PLD. All-solid-state lithium secondary batteries using the coated LiCoO 2 electrode and the Li 2S–P 2S 5 solid electrolyte were fabricated. The PLD coating of oxide film with high conductivity on LiCoO 2 was effective in decreasing the electrode/electrolyte interfacial resistance and developing power density of the all-solid-state cells.