Regulating the lithium metal growth by Li3BO3/Li2OHCl solid-state electrolyte for long-lasting lithium metal stripping-plating

Lithium-rich anti-perovskite materials, with their high theoretical Li conductivity and relatively low energy barrier for Li transport, are highly promising as an electrolyte contender in all-solid-state lithium-metal batteries. Their current performance is however compromised by the grain boundary to result in low Li conductivity and high activation energy. Herein, a composite electrolyte is prepared by introducing the glassy LiBO into the LiOHCl to serve as a bridge to connect the LiOHCl grains together to lower the impact from the grain boundary. The Li conductivity of LiOHCl can be improved by the presence of 10 wt% LiBO, and its impact on the lithium metal growth behavior is also investigated. It is found that the lithium-metal battery with LiBO/LiOHCl prefers the deposition of lithium metal particles with larger size than that in the battery with LiOHCl. Consequently, the lithium-metal symmetric cell with 10 wt% LiBO/LiOHCl is able to display excellent cycling for over 1800 h at 0.1 mA cm. The batteries with 10 wt% LiBO/LiOHCl are also able to improve the cycle stability and rate performance. The results of this study provide the direct experimental proof of the effect of grain boundary in LiOHCl on the battery performance.