Polyacrylic co-maleic acid as an anti-scaling binder for air–cathode microbial fuel cell: An oxygen reduction reaction perspective

Polydimethylsiloxane (PDMS) is a binder commonly used in air-cathode MFC fabrication. Herein, the performance of poly acrylic co-maleic acid (PMA) as a binder and anti-scaling agent for cathode was evaluated for application in an air-cathode MFC. Two different cathode catalysts were tested for applicability in MFC, viz., (a) Vulcan-XC: with PMA (MFC-1), with PDMS (MFC-3), and (b) Nitrogen-doped carbon catalyst (NDCP) with PDMS (MFC-2) and with PMA (MFC-4). The PMA, as an alternative to costly PDMS, prevented scale formation on the cathode surface and helped to sustain the performance of MFC-3 and MFC-4 for over 30 days. As evidenced by the cyclic voltammetry and electrochemical impedance spectroscopy, MFC-4 (NDCP and PMA) showed the best cathodic current density owing to the core-shell structure formed by nitrogen and carbon atoms in NDCP. In the future, using PMA can prevent scale formation over the (air) cathode surface and deliver a stable performance of MFC without any need for costly binder agents, such as PDMS.