Advances in 3D Thin-Film Li-Ion Batteries

Abstract

The status and progress toward solid-state 3D thin-film Li-ion microbatteries is reviewed. Planar thin-film batteries (TFBs) are commercially available. A major issue with planar TFBs, however, is that the total footprint capacity is limited, as only a relatively small electrode volume is available for energy storage. Coating of the complete battery thin-film stack, i.e., cathode/solid electrolyte/anode, over a 3D microstructured current collector substrate can provide higher footprint capacity as a result of the surface area enhancement. However, thus far, no 3D TFB with footprint capacity exceeding the limit of ≈250 µAh cm−2 are achieved. The authors provide a status of the individual components: thin-film cathodes, anodes, and thin-film solid electrolyte conformally coated over 3D substrates with periodic microstructures. Guidance for designing a 3D TFB with optimum capacity is also provided.