| abstract |
A method and apparatus for making thin-film batteries having composite multi-layered electrolytes with soft electrolyte between hard electrolyte covering the negative and/or positive electrode, and the resulting batteries. In some embodiments, foil-core cathode sheets each having a cathode material (e.g., LiCoO2) covered by a hard electrolyte on both sides, and foil-core anode sheets having an anode material (e.g., lithium metal) covered by a hard electrolyte on both sides, are laminated using a soft (e.g., polymer gel) electrolyte sandwiched between alternating cathode and anode sheets. A hard glass-like electrolyte layer obtains a smooth hard positive-electrode lithium-metal layer upon charging, but when very thin, have randomly spaced pinholes/defects. When the hard layers are formed on both the positive and negative electrodes, one electrode's dendrite-short-causing defects on are not aligned with the other electrode's defects. The soft electrolyte layer both conducts ions across the gap between hard electrolyte layers and fills pinholes. |