Zr- and Ce-doped Li 6 Y(BO 3 ) 3 electrolyte for all-solid-state lithium-ion battery.

The ionic conductivity of Li 6 Y(BO 3 ) 3 (LYBO) was enhanced by the substitution of tetravalent ions (Zr 4+ and Ce 4+ ) for Y 3+ sites through the formation of vacancies at the Li sites, an increase in compact densification, and an increase in the Li + -ion conduction pathways in the LYBO phase. As a result, the ionic conductivity of Li 5.875 Y 0.875 Zr 0.1 Ce 0.025 (BO 3 ) 3 (ZC-LYBO) reached 1.7 × 10 -5 S cm -1 at 27 °C, which was about 5 orders of magnitude higher than that of undoped Li 6 Y(BO 3 ) 3 . ZC-LYBO possessed a large electrochemical window and was thermally stable after cosintering with a LiNi 1/3 Mn 1/3 Co 1/3 O 2 (NMC) positive electrode. These characteristics facilitated good reversible capacities in all-solid-state batteries for both NMC positive electrodes and graphite negative electrodes via a simple cosintering process.