A thin-film battery (10) is disclosed which includes a cathode current collector (11), a cathode (12), an electrolyte (13), an anode (14), and an anode current collector (15). The cathode is produced by grinding lithium cobalt oxide or other suitable cathode material to a powder having a mean particle size of between 5 and 12 microns, forming a liquid slurry with the cathode material, casting the liquid slurry upon a substrate, drying the liquid slurry to form a layer of cathode material, and compressing the cathode layer to a generally uniform and smooth thickness of between 5 and 12 microns. The compressed layer is then heated to a temperature which sinters or melts the peripheral edges of the cathode particles together.