High-energy-density and safe rechargeable batteries are required for NASA’s future exploration missions. Lithium-ion (Li-ion) batteries are attractive energy storage systems due to their relatively high energy and power densities. However, the unfavorable side reactions between the electrodes and the liquid electrolyte adversely impact performance. These interfacial reactions are in the form of either anodic oxidation of the electrolyte, or dissolution of the cathode into the electrolyte. As a result, the practical capacity and cycle life of the battery are limited. More importantly, the reactions at the cathode-electrolyte interface pose a serious threat to safety due to the electrolyte decomposition and formation of gaseous products within the cell. In addition, growth of lithium dendrite on the anode can cause cell short circuit and lead to fire or even explosion in the presence of liquid electrolyte.
A new method was developed to process sulfide-based solid electrolyte powders so they can be cast in the form of a thin and flexible tape. This represents a major step toward transitioning solid-state electrolyte materials to a viable commercial product, and implementing a rechargeable, all-solid-state lithium-ion battery. It was demonstrated that the solid-state electrolyte dispersion can be cast in single and bi-layer tapes on a current collector. Cells using the cast solid electrolyte tape and cathode were assembled and activated with lithium metal as anode. It was demonstrated that the cell can be reversibly cycled with the newly developed solid electrolyte architecture. Additionally, the sulfide-based solid electrolyte has a relatively wide electrochemical stability window (nearly 6.0 V) and is stable against lithium anode. A wide electrochemical stability window in the solid electrolyte assists the cycling stability of the battery.
Non-NASA applications for the innovation include automotive applications such as Li-ion battery packs in hybrid electric vehicles and electric vehicles; consumer electronics such as laptops, mobile phones, cameras, camcorders, and power tools; medical devices; electric bikes/scooters; and military applications such as air, ground, emergency, and pulse power applications.