Development of a 3D porous sponge as a bioanode coated with polyaniline/sodium alginate/nitrogen-doped carbon nanotube composites for high-performance microbial fuel cells

The structure and biocompatibility of anode materials significantly affect the performance of microbial fuel cells (MFCs). A biocompatible polyaniline–sodium alginate (PANI–SA) composite was prepared in situ oxidation polymerization on the 3D porous nitrogen-doped carbon nanotube/sponge (NCNT/S) to construct a high-performance microbial fuel cell in this investigation. The SEM showed that PANI–SA composite anode had a three-dimensional macroporous structure, and nitrogen-doped nanotubes were wound around the sponge skeleton, which had a large specific surface area, provided more places for the attachment and growth of microorganisms. A dual-chamber MFC equipped with a PANI–SA/NCNT/S bioanode to achieve a power density of 4380 mW m −3 , which was much greater than the other MFCs. During the charge–discharge time of 60–90 min, the PANI–SA/NCNT/S bioanode had the highest total charge value of 26,617.86 C m −2 , which was 3.23 times higher than that of NCNT/S (8231.87 C m −2 ). High-throughput sequencing results showed that the PANI–SA/NCNT/S bioanode exhibited high community diversity and selective enrichment of electrogenic bacteria. The excellent performance of the MFC equipped with PANI–SA/NCNT/S anode was attributed to the composite materials, which could be attributed to the large-pore network structure, better biocompatibility, large capacitance and high specific surface area. Graphic abstract Illustration of the process for the preparation of PANI–SA