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

Abstract

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.

Gradient Host for Bottom-Up Deposition of Lithium Metal Anode

“…A dendrite-free Li anode is very important for long-cycle-life LMBs. − Therefore, another purpose of the Li metal anode hosts is to create the Li deposition sites and growth form according to the demands through the adjustability of the hosts themselves, to inhibit the formation of Li dendrites and dead Li. , The “bottom-up” Li deposition method is necessary since it can deposit Li metal preferentially at the bottom of the hosts, avoiding Li plating at the top of the anode, which can cause dendrites to split the separators and even produce dead Li and battery failure. , Figures c and d compare the electrochemical behavior of Li deposition/stripping in conventional and gradient hosts. For the insulating Li hosts, the bottom near the current collector is the only electron transport channel, which enables the Li metal to be preferentially deposited at the bottom of hosts.…”