Sodium Ion Battery Lecture Notes

Introduction to Sodium Ion Batteries

• Definition: Rechargeable batteries that use sodium ions as charge carriers.
• Comparison with Lithium Ion Batteries:
  • Cell construction and working principles are similar to lithium ion batteries.
  • Main difference: Sodium is used instead of lithium as the cathode material.
• Advantages of Sodium Ion Batteries:
  • Natural abundance of sodium.
  • Low cost.
  • Environmentally friendly.
  • Higher charge capacity compared to lithium ion batteries.
  • Develops up to 3V.

Construction of Sodium Ion Batteries

• Overall Design: Same as lithium ion batteries.
• Components:
  • Container: Made from stainless steel or aluminum alloy.
  • Anode:
    • Made of copper foil layers.
    • Contains graphite.
  • Cathode:
    • Made of aluminum foil layers.
    • Uses sodium cobalt oxide instead of lithium cobalt oxide.
  • Electrolyte:
    • Sodium hexafluorophosphate dissolved in organic solvents (propylene carbonate, ethylene carbonate) with a gelling agent.
  • Separator: Made of polyethylene, separates cathode and anode, allows movement of sodium ions.

Working Principle of Sodium Ion Batteries

• Charging Process:

  • Sodium ions in sodium cobalt oxide are oxidized, liberating electrons and sodium ions.
  • Electrons move through the external circuit, while sodium ions move through the electrolyte to the anode.
  • Formation of C6NaY occurs at the anode (graphite) as sodium ions are reduced to sodium atoms.
  • Battery is fully charged when all sodium ions are transferred to the anode.

• Discharging Process:

  • Sodium atoms in the anode (graphite) are oxidized, releasing electrons and sodium ions.
  • Sodium ions move back to the cathode through the electrolyte.
  • Formation of sodium cobalt oxide occurs at the cathode.
  • Battery is fully discharged when all sodium ions return to the cathode.

Applications of Sodium Ion Batteries

• UPS Applications: Uninterruptible power supplies.
• Telecommunications: Used for energy storage in telecommunications infrastructure.
• Stationary Energy Storage: Large scale energy storage solutions, particularly for renewable energy sources.