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

• Ash-free bagasse is a promising carbon–neutral DC-SOFC fuel. • Bagasse-fed SOFCs outperform biochar: 324 vs 277 mW/cm 2 @800 °C. • Direct bagasse-fed SOFC suffers cell failure due to fuel interruption. • Both fuels can cause carbon deposition on the anode. 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/cm 2 at 800 °C) than those fueled by bagasse-derived biochar (277 mW/cm 2 ), which is attributed to the in-situ generation of pyrolysis gases (H 2 /CO/CH 4 ) during operation. Durability tests revealed divergent failure mechanisms: biochar-fueled cells experienced voltage collapse after 20 h at 0.3 A/cm 2 due to carbon depletion, whereas direct bagasse operation exhibited premature failure within 10 h at 0.4 A/cm 2 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.