
80 Electrochemically Enabled Sustainability
single-chamber fuel cell, because there is no ‘cathode chamber’ for an air-
cathode MFC. However, if cells are stacked together, the air spacing between
the liquid chambers should be included for the overall fuel cell volume.
If microorganisms are grown outside the fuel cell, the volume where the
microbes grow should also be included in the total fuel cell size.
To opt for high power output MFCs, it is essential to convert as much
electrons stored in the substrates as possible into current. The recovery of
electrons measured in terms of ‘Coulombic efciency’, C
E
, is dened as the
ratio of electrons act ...