|
Anode electrode
|
| Conductivity |
Reduce resistance, improve electron transfer, lower losses |
66 and 67
|
| Improve electrochemical performance over plain carbon paper |
| Surface area |
Enhance bacterial attachment |
68 and 69
|
| More biocatalysts from organic compounds oxidation (e.g., graphite felt yields higher output power than a graphite rod because of its increased surface area) |
| Porosity and pore structure |
Maintain anoxic conditions for electricity generation in the anode |
68 and 70
|
| Large bio-accessible surface area |
| Thickness |
Minimise resistance to electron transport from the biofilm to the anode |
71
|
| Stability and durability |
pH shift tolerant conditions |
72
|
| Biocompatibility |
Facilitate bacteria–electrode interaction and higher biomass |
73–75
|
| Electro catalytic activity |
Enhancement on in situ oxidation of the microbial metabolites |
76
|
| Low cost |
Feasibility of scale-up and commercial application |
77
|
| Mechanical strength |
Better mechanical strength under a range of conditions by using carbonaceous and metallic materials (e.g., carbon paper, carbon rods, graphite felt, reticulated vitreous carbon, nickel sheets, stainless steel mesh, and copper sheets) |
68
|
| |
|
Cathode electrode
|
| Conductivity |
Polarization loss reduction |
78
|
| Oxygen reduction reaction enhancement |
| Stability and durability |
pH shift tolerant |
72
|
| Low cost |
Feasibility of scale-up and commercial application |
77
|
| Catalytic activity |
Oxygen reduction reaction enhancement |
74 and 79
|
| Lower cathodic activation energy and increase the rate of reaction |
| Biocompatibility |
Improve the biocathode biocompatibility |
78
|
| Active sites |
Enhancement in number of active sites (e.g. pyridinic and pyrrolic nitrogen) to facilitate a more efficient transfer of electrons during the oxygen reduction reaction |
74
|
| |
|
Separator membrane
|
| Stability |
To be resilient and stable in acidic and alkaline conditions |
80
|
| Conduction |
To conduct the protons to cathode, not electrons to fulfil the eqn (1) and (2) for energy generation |
81
|
| Impermeability to gases |
To allow H+ to pass from the anode to the cathode side and be impermeable to gases like H2, O2, and N2
|
82
|
| Low cost |
Feasibility of scale-up and commercial application |
80 and 83
|
| Hydrophilicity |
To facilitate cationic transport and should also inhibit oxygen diffusion |
84
|
