Realizing Safe Sodium Metal Batteries Through the Advanced Composite Na Metal Anode: Developments and Perspectives

Sodium metal batteries, with their high theoretical specific capacity and energy density, are ideal candidates for long‐duration applications. As progress in Na metal batteries continues, the demands on the anode have become increasingly stringent. However, the high reactivity of Na metal poses a significant safety challenge that limits the application of Na metal batteries. During battery cycling, Na ions continuously nucleate, deposit, and eventually form Na dendrites on the anode side. Therefore, understanding the formation mechanism of Na dendrites and the measures to prevent them plays a direct role in the further application of Na metal batteries. This review aims to enhance the understanding of the relationship between the fundamental principles of Na metal anode failure and improved design. The review focuses on the analysis and summary of the latest Na metal anodes based on commonly used carbon‐based and metal‐based matrix materials, and on optimizing the anode against dendrite formation mechanisms. Additionally, it provides a perspective on the development of Na metal anodes. A deep understanding of anode optimization engineering will pave the way for the development of practical, safe, and durable high‐performance Na metal batteries.