Review—Lithium Carbon Composite Material for Practical Lithium Metal Batteries

Abstract

Comprehensive Summary Lithium (Li) metal is considered ideal for high‐energy‐density batteries due to its extremely high specific capacity and low electrochemical potential. However, uncontrolled Li dendrite growth and interfacial instability during repeated Li plating/stripping have limited the practical applicability of Li metal batteries (LMBs). Over the past decades, substantial efforts have been devoted to solving the challenges associated with Li metal anodes. Our research team has developed several Li‐carbon (Li‐C) microsphere composites in recent years to suppress the formation of Li dendrites and achieve a decent cycle life. In this account, we summarize our advances in the design and application of Li‐C composites, which include the developments in the structure and chemical composition of high‐specific‐capacity Li‐C composites, strategies for surface passivation of the micro‐spherical Li‐C composites, and applications of the Li‐C composite in next‐generation high‐energy‐density Li‐ion, Li‐air, and solid‐state LMBs. Finally, we discuss future perspectives for developing high‐performance Li metal anodes and endeavors to realize the practical applications of LMBs. What is the most favorite and original chemistry developed in your research group? Accurate control of surface chemistry of battery materials in general, and Li metal in particular, with self‐assembled monolayers (SAM). How do you get into this specific field? Could you please share some experiences with our readers? Li metal is an ideal anode material for rechargeable batteries except that it is extremely reactive towards the environment and that the conversion reaction tends to deposit Li metal into dendrites. My group developed a Li‐C composite by infiltrating molten Li into carbon nanotube microspheres. This composite largely alleviated the dendrite growth problem of Li anode, but the reactivity of Li metal caused the Li‐C microsphere impossible to process outside Ar gloveboxes. A passivation method is needed. I recalled the molecular self‐assembly technique I learned and used in my Ph.D. dissertation, where I used the Au‐thiol SAM chemistry to control the surface chemical interactions between atomic force microscopy (AFM) probes and samples. The question is whether we can find the right chemistry between Li metal and self‐assembling molecules. This was how we started the journey of SAM on Li metal, and later further developed the idea to other battery materials such as high‐Ni NCM cathode, etc. How do you supervise your students? Students first need to build their own knowledge base, a set of scientific concepts and theoretical framework they are comfortable with and a set of experimental skills they are confident in. Then we define research directions together. Once we agree on a direction and the student starts to explore the direction with his/her knowledge and skills, here it comes the most enjoyable part of supervising students: I get to ask questions. It is through addressing questions, students learn to practice critical thinking, pol...

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