On-surface lithium donor reaction enables decarbonated lithium garnets and compatible interfaces within cathodes

Lithium garnets have been widely studied as promising electrolytes that could enable the next-generation all-solid-state lithium batteries. However, upon exposure to atmospheric moisture and carbon dioxide, insulating lithium carbonate forms on the surface and deteriorates the interfaces within electrodes. Here, we report a scalable solid sintering method, defined by lithium donor reaction that allows for complete decarbonation of Li(6.4)La(3)Zr(1.4)Ta(0.6)O(12) (LLZTO) and yields an active LiCoO(2) layer for each garnet particle. The obtained LiCoO(2) coated garnets composite is stable against air without any Li(2)CO(3). Once working in a solid-state lithium battery, the LiCoO(2)-LLZTO@LiCoO(2) composite cathode maintains 81% of the initial capacity after 180 cycles at 0.1 C. Eliminating CO(2) evolution above 4.0 V is confirmed experimentally after transforming Li(2)CO(3) into LiCoO(2). These results indicate that Li(2)CO(3) is no longer an obstacle, but a trigger of the intimate solid-solid interface. This strategy has been extended to develop a series of LLZTO@active layer materials.