A Comprehensive Study of Nonuniformity Properties of the LiCoO₂ Thin-Film Cathode Fabricated by RF Sputtering

The influence of nonuniformity properties of the LiCoO₂ cathode film deposited by magnetron sputtering on the capacity of all-solid-state thin-film lithium-ion batteries (ASSLIB) was studied. It was found that the film nonuniformity corresponds to the magnetron plasma density distribution and the angular distribution of sputtered particles. The capacity distribution of the ASSLIB with LiCoO₂ cathode depending on the distance to the substrate center was studied. The maximum capacity corresponded to the dense part of the toroidal region of the magnetron plasma. It was determined that the main causes of batteries capacity decline in the central part and on the edge of the substrate are the impurity phase of lithium cobaltate and the smaller thickness of the cathode layer, respectively.