Why can batteries generate electricity? Chemical energy turns into electric current along electron channels

The battery does not create electrons out of thin air, but allows oxidation and reduction reactions to occur at two electrodes respectively, and forces the electrons to pass through an external circuit.

Two electrodes work together

Oxidation reactions release electrons at one electrode, and reduction reactions receive electrons at the other electrode. The electrolyte moves the ions, and the external circuit provides a path for the electrons to take.

Voltage comes from chemical potential difference

Different materials have different affinities for electrons, creating a potential difference between the two electrodes. Material combination, concentration and temperature all affect the battery's voltage and output capabilities.

Charging is pushing the reaction in reverse

After the rechargeable battery is connected to an external power source, the external electric energy pushes the discharged products back to a high-energy state. Cycle life depends on whether the interface, structure and side reactions can be controlled.