High‐performance Microbial Fuel Cell Using Metal Ion Complexes as Electron Acceptors

Abstract

Metal complex‐microbial fuel cells (MFCs) have been investigated in this work with intent manufacturing highly efficient MFC batteries. The performance of metal complex MFCs was evaluated by polarization and discharge experiments using a battery consisting of three MFC unit cells. The results indicated that the performance of the [Fe(III)(4,4′‐dimethyl‐2,2′‐bipyridyl)3]‐MFC was much better than the other MFC containing Cr(VI) or Fe(III) as an electron acceptor. At a discharging current of 3 mA (17.6 A/m3), the average discharging potential was found to be 0.927 V under a parallel‐connection, sustaining longer than 20 h with an open circuit voltage of 1.210 V. [Fe(III)(4,4′‐dimethyl‐2,2′‐bipyridyl)3]‐MFC showed much higher electrochemical parameters than Cr(VI)‐MFC and Fe(III)‐MFC. Highest maximum power of 34.87 Wm−3 could be obtained from the battery consisting of three MFCs in parallel‐connection, when each cell contains a carbon brush anode and a graphite plate. MFC battery containing a carbon brush anode and a carbon brush cathode showed better polarization and discharging performance. In particular, the maximum power of 45.45 Wm−3 was achieved. By installing the maximum amount of carbon brush anode and adjusting the amount of carbon brush cathode and the electron acceptors, the magnitude of current and the maximum power can be maximized.

Contribution of configurations, electrode and membrane materials, electron transfer mechanisms, and cost of components on the current and future development of microbial fuel cells

“…In the literature also is reported the use of other electron acceptors, such as manganese dioxide, nitrobenzene, ferric iron, hydrogen phosphate, hydrogen peroxide, ferricyanide [226] , copper chloride, potassium hexacyanoferrate (K 3 [Fe(CN) 6 ]), perchlorate and nitrates , hydrochloric acid (HCl), sodium hypochlorite (NaOCl), and nitric oxide (NO) [11] , [148] , [159] , [240] , [241] , [242] . Among these, (K 3 [Fe(CN) 6 ]) is the most widely used, one of the main reasons is the low overpotential generated when carbon-based material is used as cathode [120] Additionally, the ferric ion complex increased electron transfer rates [243] .…”

Reverse electrodialysis for emerging applications

“…And as the electrical power generated from RED is easily modulated by the number of IEMs and the salinity ratio, diverse combination of RED with different technologies demonstrated its high potential as an environmentally friendly assistant power source. The combination of RED with microbial fuel cells 17 is an intriguing example that could overcome limitations of individual process (i.e., theoretical maximum voltage of exo‐electrogenic bacteria‐based fuel cell and overpotential to drive electrode reactions in RED) 18 . The first reported microbial RED cell produced up to 1.3 V and 4.3 W/m 2 (with cathode surface area) with five pairs of IEMs, using NaCl as feed solution and acetate as fuel 18 .…”