Enhanced power generation with disordered porous carbon-modified foam iron–nickel anode in human urine-driven microbial fuel cell

Abstract

Microbial fuel cell is a promising way for renewable energy recovery. The direct conversion of urine into electricity through MFC has been tested, considering that urine has rich organic substances and high conductivity, demonstrating dual benefits for electricity generation and urine treatment as a feasible method. However, it still suffers from several constraints relating to anodes, including limited bacterial loading capacity and inferior extracellular electron transfer efficiency. Substantial efforts have been made to improve electricity production, especially to develop new anodes. In this study, we prepared a new composite anode (SC-FeNi) and used it in an MFC reactor to recover energy from urine. The power density of the SC-FeNi anode could reach 524.93 mW·m−2 when using synthetic urine and increased to 1720.1 mW·m−2 when replaced with undiluted human urine, which was the highest power density in monomer MFC fueled with urine to the best of our knowledge. SC-FeNi had high conductivity (12.29 S·m−1), large specific surface area (1236.417 m²·g−1), and enriched high microorganism density (312.04 ± 15.4 mg·cm−³). The stable power generation period in batch mode reached 288 h. This experiment verified that combining foam metal and disordered porous carbon as MFC electrode materials could generate energy from human urine waste with high efficiency and durability.