Rational design of carbon skeleton interfaces for highly reversible sodium metal battery anodes

Sodium metal batteries (SMBs) have attracted increasing attention over time due to their abundance of sodium resources and low cost. However, the widespread application of SMBs as a viable technology remains a great challenge, such as uneven metallic deposition and dendrite formation during cycling. Carbon skeletons as sodiophilic hosts can alleviate the dendrite formation during the plating/stripping. For the carbon skeleton, how to rationalize the design sodiophilic interfaces between the sodium metal and carbon species remains key to developing desirable Na anodes. Herein, we fabricated four kinds of structural features for carbon skeletons using conventional calcination and flash Joule heating. The roles of conductivity, defects, oxygen content, and the distribution of graphite for the deposition of metallic sodium were discussed in detail. Based on interface engineering, the J1600 electrode, which has abundant Na-C species on its surface, showed the highest sodiophilic. There are uniform and rich F-Na species distributed in the inner solid electrolyte interface layer. This study investigated the different Na-deposition behavior in carbon hosts with distinct graphitic arrangements to pave the way for designing and optimizing advanced electrode materials.