Fundamentals of Lithium-Ion Batteries

Lithium-ion (Li-ion) batteries are widely used in portable electronics and electric vehicles due to their high energy density and long cycle life.

Working Principle

During discharge, lithium ions move from the anode (usually graphite) to the cathode (typically a lithium metal oxide), releasing electrical energy.
During charge, an external power source drives the ions back to the anode.

The overall chemical reactions are:

Discharge: - At anode: LiC₆ → C₆ + Li⁺ + e⁻
- At cathode: Li₁₋ₓCoO₂ + xLi⁺ + xe⁻ → LiCoO₂

Charge: - At anode: C₆ + Li⁺ + e⁻ → LiC₆
- At cathode: LiCoO₂ → Li₁₋ₓCoO₂ + xLi⁺ + xe⁻

Schematic Illustration