The Difference Between Electrochemical Cell and Electrolytic Cell
Electrochemistry is a branch of chemistry that deals with the relationship between electricity and chemical reactions. It is a fascinating subject that has numerous applications in everyday life, especially in the field of renewable energy. Electrochemical processes involve the transfer of electrons between a solid and a liquid, or two liquids, through a redox reaction. Electrochemical cells and electrolytic cells are two types of electrochemical systems that function differently. Here are the differences between an electrochemical cell and an electrolytic cell.
Electrochemical Cell
An electrochemical cell is a device that converts chemical energy into electrical energy. It consists of two electrodes submerged in an electrolyte, which is a solution that conducts electricity. The electrolyte contains ions that can move between the two electrodes. The chemical reaction that occurs at the electrode surface generates an electric potential difference, which drives the flow of electrons from one electrode to the other. This flow of electrons is what we refer to as an electric current.
Electrochemical cells can be divided into two categories: primary cells and secondary cells. Primary cells are not rechargeable and are designed to be used once before being discarded. Examples of primary cells are alkaline batteries and zinc-carbon batteries. The chemical reaction that takes place in these cells cannot be reversed, i.e., it cannot be recharged.
Secondary cells, on the other hand, are rechargeable and can be used multiple times. Examples of secondary cells are lead-acid batteries, nickel-cadmium batteries, and lithium-ion batteries. In these cells, the chemical reaction is reversible, and the cell can be recharged by reversing the direction of the current.
Electrolytic Cell
An electrolytic cell is a device that converts electrical energy into chemical energy. It consists of two electrodes submerged in an electrolyte, similar to an electrochemical cell. However, the difference is that the electric potential applied to the electrodes is external and not generated by the chemical reaction. The electric potential difference causes a flow of electrons from the power source to the electrodes. This flow of electrons drives a non-spontaneous chemical reaction, which converts the reactants into products.
Electrolytic cells are widely used in industry for various processes, such as electroplating, electrorefining, and electro-winning. Electroplating is a process where a metal coating is applied to a substrate, e.g., silver plating of cutlery. Electrorefining is a process used to purify metals, such as copper and nickel, while electro-winning is a process used to extract metals, such as aluminum and magnesium.
In summary, electrochemical cells convert chemical energy into electrical energy, while electrolytic cells convert electrical energy into chemical energy. Electrochemical cells are used in batteries, while electrolytic cells are used in industrial processes that require non-spontaneous reactions. Knowing the difference between these two types of electrochemical systems can help you understand their various applications.
Table difference between electrochemical cell and electrolytic cell
| Electrochemical Cell | Electrolytic Cell | |
|---|---|---|
| Process | Spontaneous redox reactions occur | Non-spontaneous redox reactions occur with the help of an external power source |
| Function | Produce electrical energy from chemical energy | Produce chemical changes by using electrical energy |
| Anode | Electrons are released from the anode and flow through the external circuit to the cathode | The anode is the positive electrode where oxidation occurs, releasing positively charged ions into the electrolyte |
| Cathode | Electrons are accepted by the cathode, where reduction takes place | The cathode is the negative electrode where reduction occurs, attracting positively charged ions from the electrolyte to form a deposit or coating |
| Electrolyte | Can be a solid, liquid, or gel that allows the flow of ions between the anode and cathode | Contains ions that are either positively or negatively charged and must be present for the reaction to occur |
| Cell potential | The potential difference between two electrodes determines the voltage of the cell | The potential difference between two electrodes is determined by the applied voltage |
| Examples | Battery, fuel cell | Electroplating, metal refining, electrolysis of water |