Preparation of amorphous Li4SiO4–Li3PO4 thin films by pulsed laser deposition for all-solid-state lithium secondary batteries

Amorphous thin film electrolytes in the system Li4SiO4–Li3PO4 were prepared by pulsed laser deposition (PLD). The ionic conductivity of the amorphous film at the composition 50Li4SiO4·50Li3PO4 (mol%) was 1.6 × 10− 6 S cm− 1 at room temperature which is higher than the conductivities of Li3PO4 and Li4SiO4 films. The 50Li4SiO4·50Li3PO4 film was coated on LiCoO2 active material particles by PLD. All-solid-state lithium secondary batteries using the coated LiCoO2 electrode and the Li2S–P2S5 solid electrolyte were fabricated. The PLD coating of oxide film with high conductivity on LiCoO2 was effective in decreasing the electrode/electrolyte interfacial resistance and developing power density of the all-solid-state cells.