The Lithium-ion Battery

The lithium-ion battery is the dominant rechargeable technology inside cell phones, laptops and digital cameras, valued for packing a large amount of energy into a comparatively light, compact cell. Its construction is:

• Anode: porous graphite.
• Cathode: a transition-metal oxide such as CoO₂.
• Electrolyte: a lithium salt dissolved in a non-aqueous organic solvent.

At the anode, lithium is oxidised: $\text{Li(s)} \rightarrow \text{Li}^{+}\text{(aq)} + e^{-}$. At the cathode, the released Li⁺ ions are taken up as the cobalt oxide cathode is reduced: $\text{Li}^{+} + \text{CoO}_2\text{(s)} + e^{-} \rightarrow \text{LiCoO}_2\text{(s)}$. Combining the two gives the overall reaction $\text{Li(s)} + \text{CoO}_2\text{(s)} \rightarrow \text{LiCoO}_2\text{(s)}$. …