Direct carbon solid oxide fuel cells fed with ash-free bagasse versus bagasse-derived biochar: A comparative study

Direct carbon solid oxide fuel cells (DC-SOFCs) have attracted considerable attention as highly efficient power generation systems. This study provides a comparative assessment of performance and operational stability of Ni-YSZ anode-supported SOFCs fueled by ash-free raw bagasse versus its pyrolyzed biochar. Structural analysis confirmed pyrolysis-driven transformation of bagasse into a carbon-enriched biochar, evidenced by an elevated C/O ratio (7.6 vs. 1.6). Electrochemical evaluation demonstrated that SOFCs operating on direct bagasse achieved higher peak power density (324 mW/cm² at 800 °C) than those fueled by bagasse-derived biochar (277 mW/cm²), which is attributed to the in-situ generation of pyrolysis gases (H₂/CO/CH₄) during operation. Durability tests revealed divergent failure mechanisms: biochar-fueled cells experienced voltage collapse after 20 h at 0.3 A/cm² due to carbon depletion, whereas direct bagasse operation exhibited premature failure within 10 h at 0.4 A/cm² owing to fuel supply discontinuity. This study reveals that ash-free bagasse is a promising carbon–neutral fuel for SOFCs, and underscores the need for strategies to ensure continuous fuel delivery for sustained operation.