Mechanism of enhanced performance on a hybrid direct carbon fuel cell using sawdust biofuels

Biomass is expected to play a significant role in power generation in the near future. With the uprising of carbon fuel cells, hybrid direct carbon fuel cells (HDCFCs) show its intrinsic and incomparable advantages in the generation of clean energy with higher efficiency. In this study, two types of biomass treated by physical sieve and pyrolysis from raw sawdust are investigated on an anode-supported HDCFC. The structure and thermal analysis indicate that raw sawdust has well-formed cellulose I phase with very low ash. Electrochemical performance behaviors for sieved and pyrolyzed sawdust combined with various weight ratios of carbonate are compared in N₂ and CO₂ purge gas. The results show that the power output of sieved sawdust with 789 mWcm⁻² is superior to that of pyrolyzed sawdust in CO₂ flowing, as well as in N₂ flowing. The anode reaction mechanism for the discrepancy of two fuels is explained and the emphasis is also placed on the modified oxygen-reduction cycle mechanism of catalytic effects of Li₂CO₃ and K₂CO₃ salts in promoting cell performance.