Techno-economic analysis of cost-competitive hard carbon production from biomass for sodium-ion batteries

Sodium-ion batteries (SIBs) have gained increasing attention as a promising alternative to lithium-ion batteries due to sodium's abundance and cost-effectiveness. This growing interest in SIBs has spurred the development of hard carbon as a high-performance anode material. Although the electrochemical performance of biomass-derived hard carbon has been extensively investigated, the economic perspectives of its production have received limited attention, hindering its commercialization. To bridge this gap, this study presents the first comprehensive techno-economic analysis evaluating energy and water consumptions and costs of producing hard carbon from biomass. Considering the high water demand and wastewater generation in hard carbon production, two scenarios are analyzed: Scenario 1 discharges wastewater to municipal wastewater treatment plant, and Scenario 2 internally recycles wastewater through anaerobic and aerobic digestion. The results reveal that annually producing 110,441 tonnes of hard carbon from 576,000 tonnes of biomass requires an estimated total capital investment of 90.2 million USD, with a minimum carbon selling price (MCSP) of 1.72 USD/kg. Incorporating an internal wastewater treatment and recycling (Scenario 2) raises investment to 125 million USD but significantly reduces water and energy consumptions, lowering the MCSP to 1.58 USD/kg. This value is notably lower than the current hard carbon selling price and competitive with graphite, underscoring the cost competitiveness of biomass-derived hard carbon. Overall, our findings demonstrate an economically viable pathway for producing battery-grade hard carbon, supporting the advancement of sustainable energy storage technologies.