Electrochemical Cells: A Brief Overview


Electrochemical cells: Devices that convert chemical energy to electrical energy (galvanic) or vice versa (electrolytic). They are essential in various applications, from batteries to industrial processes.

Galvanic Cells (Batteries)

●     Principle: Spontaneous redox reactions generate electrical energy.

●     Components:

○     Anode: The electrode where oxidation occurs.

○     Cathode: The electrode where reduction occurs.

○     Electrolyte: A solution or gel that conducts ions between the electrodes.

○     Salt bridge: A porous barrier that allows ions to flow but prevents the solutions from mixing.

●     Example: A zinc-copper battery. Zinc is oxidized at the anode, releasing electrons that flow through the external circuit to the cathode, where copper ions are reduced.

Electrolytic Cells

●     Principle: Electrical energy is used to drive non-spontaneous redox reactions.

●     Components: Similar to galvanic cells, but with an external power source connected to the electrodes.

●     Applications: Electroplating, production of metals from their ores, and electrolysis of water.

Key Terms:

●     Electrode: A conductor through which electrical current enters or leaves a cell.

●     Electrolyte: A substance that conducts electricity when dissolved in a solvent.

●     Half-reaction: A balanced chemical equation representing either the oxidation or reduction process.

●     Cell potential: The voltage difference between the anode and cathode.

●     Standard reduction potential: The potential of a half-reaction under standard conditions.

Factors Affecting Cell Potential:

●     Nature of the electrodes: The type of metals used affects the cell potential.

●     Concentration of electrolytes: Higher concentrations generally lead to higher cell potentials.

●     Temperature: Increasing temperature usually increases cell potential.

Applications of Electrochemical Cells:

●     Batteries: Powering devices like smartphones, laptops, and cars.

●     Corrosion prevention: Using sacrificial anodes to protect structures from corrosion.

●     Electroplating: Coating metals with other metals for decorative or functional purposes.

●     Electrolysis: Producing pure substances from compounds, such as chlorine gas from sodium chloride.

By understanding the principles of electrochemical cells, you can better appreciate their role in various technological and industrial applications.