Carbon-based current collector materials for sodium metal anodes

Room temperature sodium-ion batteries are the most likely alternative to lithium-ion batteries, and are considered one of the most promising candidates for large-scale energy storage. On the anode side, metallic sodium, with an ultra-high theoretical capacity and a low redox potential, has been considered the most promising material for batteries with a high energy density. However, the use of a sodium metal anode has met some challenging problems, such as the growth of sodium dendrites, side reactions between sodium metal and the electrolyte, and large volume changes during charge and discharge. Among them, the growth of sodium dendrites not only produces "dead" sodium and accelerates side reactions, leading to a rapid capacity decay, but the dendrites may also pierce the separators, causing serious safety problems such as fire and battery explosion. Carbon-based materials are a large family, with a high mechanical strength, low density, high conductivity, large specific surface area and good chemical stability. In recent years, they have been widely used as the current collectors for Na metal anodes. This article reviews recent research progress on carbon-based current collector materials for sodium metal anodes, analyzes the relationship between their interface and structure, and the performance of the sodium metal anodes. Finally, problems faced by future research on carbon-based current collectors are discussed.