A new class of amorphous cathode active material Li x M y PO z (LiMPO) is proposed. The materials are sputter deposited to thin film form by Li3PO4 together with metal or metal oxide targets. Among several materials tested as thin-film battery, working material found are M = Ni, Cu, Co, Mn, Au, Ag, Pd. The property is intensively studied for Li x Cu y PO z (LiCuPO) and Li x Ni y PO z (LiNiPO). Those materials shows wide composition margin such as composition y between 1 and 3, and high capacity for LiNiPO with maximum value of 330 mAh g−1. The capability to charge and discharge at high rate is shown up to 30 C. This preliminary report reveals its high potentiality for further optimization.