Polarization curve - volt-ampere characteristic curve (V-I)

Polarization is the change in battery voltage and electrode potential caused by the transition of the electrode from the resting state (i=0) to the working state (i>0).

Polarization represents the energy loss of the battery when it transitions from a resting state to a working state.

activation polarization

Ohmic polarization

concentration polarization

Increase the true surface area of ​​the electrode

Reduce boundary layer thickness for liquid phase mass transfer

electron channel

gas diffusion

ion channel

liquid water migration channel

For electrodes with back pressure on the reactant gas, the reactant gas pressure needs to be controlled, or the electrolyte membrane should have a good gas barrier function to ensure that the reactant gas does not penetrate the pore layer of the electrode and reach the electrolyte.

For electrodes where the reaction gas and the electrolyte are of equal pressure or the reaction gas pressure is lower than the electrolyte pressure, a breathable liquid-blocking layer must be installed on the gas side of the electrode.

High true specific surface area

High ultimate diffusion current density

High exchange current density

Stabilization of the reaction zone

fuel cell voltage efficiency

fuel utilization

1. Law of Conservation of Energy: Energy cannot disappear or be created out of thin air, but can only be transferred from one object to another.

2. Energy directionality: Energy cannot spontaneously transfer from low-temperature objects to high-temperature objects without other changes.

△G=-nFE (Constant temperature and constant voltage, the maximum electrical work a system can do is equal to the reduction of Gibbs free energy)

Q=nFN

Faraday's constant (F): the charge carried by 1 mol of electrons (96500C/mol)