Partial Delignification of Bamboo for Fabricating High-Performance Porous Carbon Electrodes in Supercapacitors

This work tackles the critical issue of biomass composition effects on carbon material quality by introducing a strategic methodology: alkaline sulfite-mediated partial delignification of bamboo to precisely control and enhance the resulting porous carbon microstructure. Using bamboo as the raw material, porous carbon materials were prepared through pretreatment for varying durations to partially remove lignin, followed by precarbonization and KOH activation. Systematic investigations reveal that moderate lignin removal is critical for constructing an ideal porous structure: retention of lignin leads to disordered carbon structures and pore blockage, while excessive removal compromises the integrity of the carbon framework. Conversely, selective lignin extraction mitigates its detrimental structural impacts while retaining cellulose's ordered architecture, thereby enhancing pore size distribution and maximizing surface area. After 6 h pretreatment, BC-6 carbon exhibits ideal micropore-mesopore synergy with a 1553 m² g^-1 surface area, markedly exceeding untreated and overprocessed materials. This architecture yields 305.0 F g^-1 capacitance at 0.5 A g^-1 with complete stability over 10,000 cycles. The symmetric device delivers 13.83 W h kg^-1 at 150 W kg^-1, retaining 93.1% capacitance after 10,000 cycles. These results validate controlled delignification as crucial for optimizing bamboo carbon structure and electrochemical performance, offering innovative strategies for biomass valorization and electrode design.