Disclosed are solid-state batteries having improved energy density and methods of manufacturing the solid-state batteries having improved energy density. In some embodiments, the solid-state battery may include a substrate of yttria-stabilized zirconia, a cathode current collector formed on the substrate, an anode current collector formed on the substrate, a cathode of lithium cobalt oxide in electrical contact with the cathode current collector, an anode of lithium in electrical contact with the anode current collector, and a solid-state electrolyte of lithium phosphorous oxynitride formed between the cathode and the anode.