Electrochemical cells

Introduction to Electrochemical Cells

  • Electrochemical cells are devices that facilitate a spontaneous redox reaction to convert chemical energy into electrical energy.
  • They are typically comprised of two electrodes (anode and cathode) immersed in an electrolyte.
  • The anode is the electrode where oxidation occurs. It is generally depicted as the negative “-“ pole of the cell.
  • The cathode is the electrode where reduction happens. It is regularly portrayed as the positive “+” pole of the cell.

Types of Electrochemical Cell

  • The two primary types of electrochemical cells are galvanic cells (or voltaic cells) and electrolytic cells.
  • Galvanic cells generate an electric current from a spontaneous redox reaction. They convert chemical energy into electrical energy.
  • Electrolytic cells apply an external electric current to drive a non-spontaneous redox reaction. They convert electrical energy into chemical energy.

Operating an Electrochemical Cell

  • When an electrochemical cell is activated, the half reaction at the anode will release electrons. This generates an oxidation process. The released electrons will then flow through an electric circuit to the cathode.
  • At the cathode, the half reaction will consume these electrons, triggering a reduction process.
  • This electron flow from anode to cathode will generate an electric current.

Electrolytes and Salt Bridges

  • The electrolyte in an electrochemical cell allows ionic conduction, enabling the exchange of charges between the two half cells.
  • A salt bridge is used to balance out charge in the solution. It enables the flow of ions between the two half cells, preventing their solutions from becoming electrically charged, which would prevent further reaction.

Electrochemical Cell Notation

  • The standard notation for electrochemical cells is **anode anode electrolyte   cathode electrolyte cathode**.

Applications of Electrochemical Cells

  • Electrochemical cells have numerous applications, such as in batteries, corrosion prevention, electroplating, and the production of chemicals.

Remember, conceptualising electrochemical cells and their processes is pivotal in understanding how redox reactions can be used to generate electrical energy.