Tape-casting electrode architecture permits low-temperature manufacturing of all-solid-state thin-film microbatteries

Abstract

Along with the constantly evolving functional microsystems toward more diversification, the more rigorous design deliberation of pursuing higher mass-loading of electrode materials and low-temperature fabrication compatibility have imposed unprecedented demand on integrable all-solid-state thin-film microbatteries. While the classic thin-film intercalation cathode prepared by vacuum-based techniques inevitably encountered a post-annealing process, tape-casting technologies hold great merits both in terms of high-mass loading and low-temperature processing. In this work, a novel microbattery configuration is developed by the combination of traditional tape-casting thick electrodes and sputtered inorganic thin-film solid electrolytes (~3 μm lithium phosphorus oxynitride). Enabled by physically pressed or vapor-deposited Li as an anode, solid-state batteries with tape-casted LiFePO₄ electrodes exhibit outstanding cyclability and stability. To meet integration requirements, LiFePO₄/LiPON/Si microbatteries were successfully fabricated at low temperatures and found to achieve a wide operating temperature range. This novel configuration has good prospects in promoting the thin-film microbattery enabling a paradigm shift and satisfying diversified requirements.