Artificial Solid Electrolyte Interphase Engineering toward Dendrite-Free Lithium Anodes

As lithium (Li) metal has the highest specific capacity (3860 mAh g^-1) and lowest anode potential (−3.04 V vs SHE), it is considered as the optimal choice of anode materials for new energy storage devices. However, the unstable Li plating/stripping behavior of the solid electrolyte interphase (SEI) on the Li anode surface triggers the common Li dendrite growth and side reactions between Li metal and electrolytes. The construction of an artificial SEI on the surface of lithium anodes is one of the effective approaches to improve the ionic conductivity, suppress the growth of lithium dendrite, and address the problem of low reversibility of lithium anodes. However, it remains a difficult problem to construct a uniform artificial SEI due to the lack of stability. Herein, an artificial Li₃BO₃ SEI film is synthesized through a facile, environmentally friendly, and inexpensive in situ reaction between boric acid and anodes to address the difficult issues. The artificial Li₃BO₃ protective layer exhibits a stable dendrite-free cycling behavior after 900 h at 1.0 mA cm^-2 in the Li symmetrical cell. The Coulombic efficiency of the Li|LiFePO₄ batteries is close to 100% after 500 cycles, which is better than those of the unmodified bare samples. In addition, Li-Li₃BO₃ also shows excellent electrochemical performance in lithium-sulfur (Li-S) batteries. These innovative findings provide new insights into the interfacial issues of Li metal anode protection and are expected to be a promising strategy for stable Li metal batteries.