Artificial\nSolid Electrolyte Interphase Engineering\ntoward Dendrite-Free Lithium Anodes

Abstract

As lithium (Li) metal has the highest specific capacity\n(3860 mAh\ng^–1) and lowest anode potential (−3.04 V\nvs SHE), it is considered as the optimal choice of anode materials\nfor new energy storage devices. However, the unstable Li plating/stripping\nbehavior of the solid electrolyte interphase (SEI) on the Li anode\nsurface triggers the common Li dendrite growth and side reactions\nbetween Li metal and electrolytes. The construction of an artificial\nSEI on the surface of lithium anodes is one of the effective approaches\nto improve the ionic conductivity, suppress the growth of lithium\ndendrite, and address the problem of low reversibility of lithium\nanodes. However, it remains a difficult problem to construct a uniform\nartificial SEI due to the lack of stability. Herein, an artificial\nLi₃BO₃ SEI film is synthesized through a facile,\nenvironmentally friendly, and inexpensive in situ reaction between\nboric acid and anodes to address the difficult issues. The artificial\nLi₃BO₃ protective layer exhibits a stable dendrite-free\ncycling behavior after 900 h at 1.0 mA cm^–2 in the\nLi symmetrical cell. The Coulombic efficiency of the Li|LiFePO₄ batteries is close to 100% after 500 cycles, which is better\nthan those of the unmodified bare samples. In addition, Li-Li₃BO₃ also shows excellent electrochemical performance\nin lithium–sulfur (Li–S) batteries. These innovative\nfindings provide new insights into the interfacial issues of Li metal\nanode protection and are expected to be a promising strategy for stable\nLi metal batteries.