Liquid metal as an efficient protective layer for lithium metal anodes in all-solid-state batteries

Lithium metal batteries with inorganic solid-state electrolytes have emerged as strong and attractive candidates for electrochemical energy storage devices because of their high-energy content and safety. Nonetheless, inherent challenges of deleterious lithium dendrite growth and poor interfacial stability hinder their commercial application. Herein, we report a liquid metal-coated lithium metal (LM@Li) anode strategy to improve the contact between lithium metal and a Li6PS5Cl inorganic electrolyte. The LM@Li symmetric cell shows over 1000 h of stable lithium plating/stripping cycles at 2 mA cm-2 and a significantly higher critical current density of 9.8 mA cm-2 at 25 degrees C. In addition, a full battery assembled with a high-capacity composite LiNbO3@LiNi0.7Co0.2Mn0.1O2 (LNO@NCM721) cathode shows stable cycling performance. Experimental and computational results have demonstrated that dendrite growth tolerance and physical contact in solid-state batteries can be reinforced by using LM interlayers for interfacial modification. Our study shows that the introduction of a liquid metal fluid interlayer with self-healing can play an essential role in stabilizing the chemical and mechanical interface between solid-state electrolyte and lithium metal to reduce the deleterious effects of volume expansion or dendrites on the electrode material. This excellent performance of symmetric cells with liquid metal-coated lithium metal can be attributed to the homogeneous lithium plating/exfoliation process facilitated by the liquid metal interlayer. image