Rapid thermal processing of garnet-based composite cathodes

Abstract

Rapid thermal annealing techniques enable quick and non-contact processing of ceramic materials and are particularly promising for materials containing elements with high vapor pressure. For example, Li-ion conductive oxide-ceramics such as the garnet-type Li7La3Zr2O12 (LLZO) need to be densified in order to be used as separators or in composite cathodes of all-solid-state batteries (ASB), but suffer from lithium loss at elevated temperatures. To address this issue, the sintering method “rapid thermal processing” (RTP) is used to fabricate ceramic composite cathodes of LLZO and LiCoO2 (LCO), the cathode active material. The cathodes were deposited on LLZO separators by screen-printing, a scalable industrial process for the fabrication of ceramic components. A detailed analysis by Raman spectroscopy and X-ray diffraction analysis confirms the successful mitigation of secondary phase formation between LCO and LLZO. The subsequent application of In-metal anodes resulted in fully inorganic ASB that were electrochemically cycled.