High Value Utilization of Waste Biomass Carbon for Rapid CO ₂ Electroreduction and Stable Sodium‐Ion Storage

ABSTRACT In the context of carbon neutrality, collaborative “power generation‐energy storage” system is an inevitable requirement for promoting the green transformation of energy structure. However, the design of related key materials still faces severe challenges. Here, a strategy for the combined use of energy materials is proposed, in which carbon materials derived from discarded bamboo are simultaneously applied to direct carbon solid oxide fuel cell (DC‐SOFC) and sodium‐ion battery (SIB), forming a resource complementary energy loop. By comparing rapid Joule heating with traditional tube furnace heating processes, the system elucidates the regulating mechanisms of the carbon material microstructure and their strengthening effect on the electrochemical performance. When the optimized carbon material is used as DC‐SOFC fuel, a maximum power density of 515.3 mW cm −2 and 1570 mAh of electricity can be achieved; As an SIB anode, it exhibits a reversible capacity of 327.6 mAh g −1 with an initial Coulombic efficiency of 90.4%. This work not only realizes the high‐value utilization of waste biomass, but also provides feasible material basis and technical ideas for building future integrated and clean energy systems.