Raw Sugarcane Bagasse Hydrochar Outperforms Carbon Nanotubes in Microbial Fuel Cell Power Generation

The commercialization of microbial fuel cells (MFCs) is currently limited by the high cost of standard electrode materials like carbon nanotubes (CNTs). This study introduces a high-performance, low-cost alternative: sugarcane bagasse hydrochar. We evaluated raw (RSBH), phosphated (PSBH), and sulfonated (SSBH) hydrochars as symmetric electrodes against a commercial CNT control. While acid functionalization enhanced thermal stability and char yields, the unmodified hydrochar yielded the most striking electrochemical results. Ni-RSBH achieved a peak power density of 1008 mW/m2, quadrupling the performance of the commercial Ni-CNT (235 mW/m2). Post-operation analysis revealed that Ni-RSBH developed exceptional biofilm compatibility, with anodic capacitance surging to 51.03 F/g compared to just 3.01 F/g for Ni-CNT. Although the phosphated variant (Ni-PSBH) offered superior voltage stability (0.68–0.71 V), the raw hydrochar provided the optimal balance of conductivity and biological activity. These findings demonstrate that minimally processed agricultural waste can outperform engineered nanomaterials, presenting a scalable, circular-economy solution for bioelectrochemical systems.