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 Li 3 BO 3 into the Li 2 OHCl to serve as a bridge to connect the Li 2 OHCl grains together to lower the impact from the grain boundary. The Li  +  conductivity of Li 2 OHCl can be improved by the presence of 10 wt% Li 3 BO 3 , and its impact on the lithium metal growth behavior is also investigated. It is found that the lithium-metal battery with Li 3 BO 3 /Li 2 OHCl prefers the deposition of lithium metal particles with larger size than that in the battery with Li 2 OHCl. Consequently, the lithium-metal symmetric cell with 10 wt% Li 3 BO 3 /Li 2 OHCl is able to display excellent cycling for over 1800 h at 0.1 mA cm −2 . The batteries with 10 wt% Li 3 BO 3 /Li 2 OHCl 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 Li 2 OHCl on the battery performance.