Electrochemical Cells and Their Applications - SS1 Chemistry Lesson Note

Electrochemical cells are devices that convert chemical energy into electrical energy through redox reactions. They play a vital role in various scientific and technological applications, ranging from energy storage and generation to electroplating and corrosion prevention. We delve will into the world of electrochemical cells, exploring their working principles, types, and diverse applications.

 

Working Principles of Electrochemical Cells:

Electrochemical cells consist of two electrodes, a conductive electrolyte, and a separator. The electrodes are typically made of different materials and are immersed in an electrolyte solution. The redox reactions occurring at the electrodes involve the transfer of electrons through an external circuit, creating an electric current.

Types of Electrochemical Cells:

1. Galvanic Cells (Voltaic Cells): Galvanic cells are spontaneous electrochemical cells that convert chemical energy into electrical energy. They consist of two half-cells, each containing an electrode immersed in an electrolyte solution. The redox reaction occurs spontaneously, generating an electric current.

 

1. Electrolytic Cells: Electrolytic cells are non-spontaneous electrochemical cells that require an external power source to drive the redox reaction in the opposite direction. They are used for processes such as electroplating, electrolysis, and the production of chemicals.

 

1. Fuel Cells: Fuel cells are electrochemical cells that generate electricity through the continuous supply of fuel and oxidant. They convert the chemical energy of a fuel, such as hydrogen or methanol, directly into electrical energy, with water as the main byproduct. Fuel cells are known for their high energy efficiency and are used in various applications, including transportation and stationary power generation.

 

Applications of Electrochemical Cells:

1. Energy Storage and Conversion: Electrochemical cells are widely used in energy storage devices, such as batteries. Rechargeable batteries, including lithium-ion batteries, lead-acid batteries, and nickel-cadmium batteries, rely on electrochemical reactions to store and release energy efficiently. These batteries are essential in portable electronics, electric vehicles, and renewable energy systems.

 

1. Electroplating and Metal Refining: Electrochemical cells are used in electroplating processes, where a metal is deposited onto a surface to enhance its appearance, protect against corrosion, or provide functional properties. Electrolytic cells are also employed in metal refining processes, such as the purification of copper and the extraction of aluminium.

 

1. Corrosion Prevention: Electrochemical cells are utilised in cathodic protection systems to prevent the corrosion of metal structures and equipment. By creating a controlled electrochemical reaction, such as sacrificial anode cathodic protection or impressed current cathodic protection, the metal being protected acts as the cathode, inhibiting the corrosion process.

 

1. Sensors and Analytical Techniques: Electrochemical cells are integral to various sensing and analytical techniques. Electrochemical sensors are used to detect and measure the concentration of substances in fields such as environmental monitoring, biomedical analysis, and food safety. Techniques like cyclic voltammetry and chronoamperometry utilise electrochemical cells to study reaction kinetics, electrode processes, and redox properties of substances.

 

1. Environmental Applications: Electrochemical cells have environmental applications, such as wastewater treatment and air pollution control. Electrochemical methods, like electrocoagulation and electrooxidation, are employed for the removal of contaminants from water, while electrostatic precipitators use electrochemical principles to capture and remove particulate matter from industrial emissions.
2. Biomedical and Bioengineering: Electrochemical cells are utilised in biomedical devices, including glucose sensors for diabetes management and neurostimulation devices. They also play a role in bioengineering applications, such as biofuel cells that harness the energy from biological processes

 

Advancements and Future Directions:

Research and development in electrochemical cells are ongoing, aiming to improve their performance, energy efficiency, and sustainability. Advances in materials science, nanotechnology, and electrocatalysis are enabling the development of new electrode materials, electrolytes, and catalysts, enhancing the capabilities of electrochemical cells for energy storage, conversion, and environmental applications. Additionally, the integration of electrochemical cells with renewable energy sources, such as solar and wind power, is a promising avenue for sustainable energy generation.