| Purpose |
To drive a non-spontaneous chemical reaction by using an external electrical energy source. |
To generate electrical energy from a spontaneous chemical reaction. |
| Energy Conversion |
Electrical energy is converted into chemical energy. |
Chemical energy is converted into electrical energy. |
| Electrodes |
Requires two electrodes, typically made of inert materials (e.g., platinum, graphite). |
Requires two electrodes, one made of a metal or other reactive substance, and the other typically made of an inert material (e.g., platinum). |
| Electrolyte |
Typically uses an electrolyte solution (e.g., a salt solution or an acid). |
Usually uses an electrolyte solution (e.g., salt bridge or an ionic solution), but not always (e.g., some dry cells). |
| Redox Reaction |
Involves a non-spontaneous redox reaction, and electrons are forced to move from the anode to the cathode. |
Involves a spontaneous redox reaction, and electrons flow naturally from the anode to the cathode. |
| Electrical Output |
Produces electrical energy as a result of the input electrical energy. |
Generates electrical energy as a result of the spontaneous chemical reaction. |
| Anode/Cathode |
The anode is positive, and the cathode is negative. |
The anode is negative, and the cathode is positive. |
| Chemical Changes |
Electrolysis leads to chemical changes in the substances within the electrolyte. |
Chemical changes occur in the anode and cathode materials during the redox reaction. |
| Examples |
Electroplating, water electrolysis, and electrorefining. |
Batteries, fuel cells, and galvanic cells (e.g., Daniell cell). |
