Emerging Carbon Nanotube-Based Nanomaterials for Stable and Dendrite-Free Alkali Metal Anodes: Challenges, Strategies, and Perspectives

Alkali metals (Li, Na, and K) are promising candidates for high-performance rechargeable alkali metal battery anodes due to their high theoretical specific capacity and low electrochemical potential. However, the actual application of alkali metal anodes is impeded by the challenges of alkali metals, including their high chemical reactivity, uncontrolled dendrite growth, unstable solid electrolyte interphase, and infinite volume expansion during cycling processes. Introducing carbon nanotube-based nanomaterials in alkali metal anodesis an effective solution to these issues. These nanomaterials have attracted widespread attention owing to their unique properties, such as their high specific surface area, superior electronic conductivity, and excellent mechanical stability. Considering the rapidly growing research enthusiasm for this topic in the last several years, we review recent progress on the application of carbon nanotube-based nanomaterials in stable and dendrite-free alkali metal anodes. The merits and issues of alkali metal anodes, as well as their stabilizing strategies are summarized. Furthermore, the relationships among methods of synthesis, nano- or microstructures, and electrochemical properties of carbon nanotube-based alkali metal anodes are systematically discussed. In addition, advanced characterization technologies on the reaction mechanism of carbon nanotube-based nanomaterials in alkali metal anodes are also reviewed. Finally, the challenges and prospects for future study and applications of carbon nanotube-based AMAs in high-performance alkali metal batteries are discussed.