Fabrication and characterization of an Li---Mn---O thin-film cathode for rechargeable lithium microbatteries

Thin films of LiMn2O4 spinel were fabricated by r.f. magnetron sputtering. The fresh films were amorphous but could be crystallized into a spinel structure by rapid thermal annealing in an oxygen ambient. The electrochemical performance of LiMn2O4 thin-film cathode was tested in LiMn2O4 thin-film (2000 Å)/1 M LiClO4 in propylene carbonate + dimethoxyethane/Li metal arrangements. LiMn2O4 spinel films prepared at 750°C has a favorable structure and grains for lithium-ion intercalation. Room temperature cycling of these films showed good intercalation kinetics and very promising cycling behavior.