Energy‐Efficient Induction Carbonization: Tailoring Pore Structures in Hard Carbon Anodes Toward Enhanced Electrochemical Performance

Hard carbon (HC) is currently the predominant anode material for sodium-ion batteries; however, its practical application is still limited by insufficient initial Coulombic efficiency (ICE) and plateau capacity. Meanwhile, conventional HC production relies on energy-intensive carbonization processes with considerable carbon emissions. Here, an induction heating carbonization strategy is developed for extruded biocarbon columns derived from biomass-based biochar and bio-oil, enabling simultaneous enhancement of electrochemical performance and production sustainability. Bio-oil combined with high-pressure extrusion suppresses open pores, whereas induction heating generates localized eddy currents and concentrated Joule heating that accelerate carbon rearrangement and promote closed pore formation. As a result, the closed-to-open pore volume ratio increases from 0.32 to 85.18, leading to improved ICE (95.0% vs. 84.4%) and plateau capacity ratio (77.6% vs. 64.7%) relative to conventional carbonized HC. Life-cycle assessment further indicates an approximately 35% reduction in global warming potential. Overall, this work presents an energy-efficient, low-emission route for producing high-performance HC anodes.