Novel Method for Floating Synthesizing Heavy Metal Particles as Flowing Anode of Zinc-Air Fuel Cell
Table 1
Causes of three types of overvoltage and their solutions.
ā
Cause
Solution
Activation overvoltage
If ions are absorbed on the electrode surface, the reaction mechanism by which O2 changed to OHā ions will slow down. This leads to activation polarization and results in activation overvoltage
Elevate the temperature of a cell, as well as the reaction speed of three-phase boundaries
Concentration overvoltage
Because of poor gas diffusion, O2 supply in the reaction becomes too slow; as a result, O2 concentration becomes insufficient. This causes concentration polarization and results in concentration overvoltage
Elevate the flow speed of O2 at the anode and increase the O2 concentration
Ohmic overvoltage
Because of improper design, poor conductivity of electrolytes or impurities in the electrodes increasing resistance to current flow, ohmic polarization may occur, resulting in ohmic overvoltage
Use electrode materials and electrolytes with higher conductivity