Electrochemical Cell

Electrochemical Cell

Definition

• An electrochemical cell is a device that converts chemical energy into electrical energy or vice versa.
• It consists of two half-cells: an anode and a cathode, separated by an electrolyte.

Types of Electrochemical Cells

• Galvanic Cell (Voltaic Cell)
  • Spontaneous redox reaction, generates electricity
  • Example: Zinc-Copper cell
• Electrolytic Cell
  • Non-spontaneous redox reaction, requires external electricity
  • Example: Electrolysis of water

Components of an Electrochemical Cell

• Anode
  • Oxidation occurs, electrons are released
  • Typically made of a material that can be oxidized easily (e.g., zinc)
• Cathode
  • Reduction occurs, electrons are consumed
  • Typically made of a material that can be reduced easily (e.g., copper)
• Electrolyte
  • Facilitates the flow of ions between the anode and cathode
  • Can be a solid, liquid, or gel-like substance
• Salt Bridge
  • Connects the two half-cells, allowing ions to flow
  • Maintains electrical neutrality in each half-cell

Electrochemical Cell Reactions

• Oxidation Half-Reaction
  • Occurs at the anode, electrons are released
• Reduction Half-Reaction
  • Occurs at the cathode, electrons are consumed
• Overall Cell Reaction
  • Combination of oxidation and reduction half-reactions

Cell Potential and Free Energy

• Cell Potential (Ecell)
  • The voltage generated by the electrochemical cell
  • Measured in volts (V)
• Standard Cell Potential (E°cell)
  • The cell potential under standard conditions (1M concentrations, 25°C, 1 atm)
• Free Energy (ΔG)
  • The energy available to do work in the electrochemical cell
  • Related to cell potential by the equation: ΔG = -nFEcell

Electrochemical Cell

Definition and Function

• Converts chemical energy into electrical energy or vice versa
• Consists of two half-cells: an anode and a cathode, separated by an electrolyte

Types of Electrochemical Cells

• Galvanic Cell (Voltaic Cell)
  • Spontaneous redox reaction, generates electricity
  • Example: Zinc-Copper cell
• Electrolytic Cell
  • Non-spontaneous redox reaction, requires external electricity
  • Example: Electrolysis of water

Components of an Electrochemical Cell

• Anode
  • Oxidation occurs, electrons are released
  • Typically made of a material that can be oxidized easily (e.g., zinc)
• Cathode
  • Reduction occurs, electrons are consumed
  • Typically made of a material that can be reduced easily (e.g., copper)
• Electrolyte
  • Facilitates the flow of ions between the anode and cathode
  • Can be a solid, liquid, or gel-like substance
• Salt Bridge
  • Connects the two half-cells, allowing ions to flow
  • Maintains electrical neutrality in each half-cell

Electrochemical Cell Reactions

• Oxidation Half-Reaction
  • Occurs at the anode, electrons are released
• Reduction Half-Reaction
  • Occurs at the cathode, electrons are consumed
• Overall Cell Reaction
  • Combination of oxidation and reduction half-reactions

Cell Potential and Free Energy

• Cell Potential (Ecell)
  • The voltage generated by the electrochemical cell
  • Measured in volts (V)
• Standard Cell Potential (E°cell)
  • The cell potential under standard conditions (1M concentrations, 25°C, 1 atm)
• Free Energy (ΔG)
  • The energy available to do work in the electrochemical cell
  • Related to cell potential by the equation: ΔG = -nFEcell