Every electro-chemical battery has one or more cells. Each individual cell in turn comprises a positive cathode electrode, a negative anode electrode, and a solid or liquid electrolyte. Lithium-ion batteries refine this design with a unique combination of materials. Today we discuss this particular blend in terms of lithium-ion battery operating principles.
The Unique Blend Operating Lithium-Ion Batteries
Silvery lithium metal is highly reactive in its natural form, and not practical to use in battery cells. Battery developers therefore developed a milder lithium-metal oxide, such as lithium-cobalt oxide to use instead.
The basic lithium-ion battery operating model is typically lithium-metal oxide for the positive cathode, and a lithium-carbon compound for the anode. These two materials readily accept lithium-ions moving between them:
When a lithium-ion battery discharges via an external circuit:
- Positively-charged lithium ions move from the negative anode to the positive cathode.
- Meanwhile, electrons move via the external circuit to balance the electrical charge.
The exact opposite flow occurs when a lithium-ion battery recharges via an external source. This ebb-and-flow can continue hundreds of times if the battery remains in good condition.
Lithium-Ion Batteries Are Ideal for Mobile Applications
Battery size and weight are important for mobile devices like smartphones and wearables. Lithium-ion technology currently has the greatest charge density (stored energy) per weight and volume:
- Lithium is the most electro-positive element on the table.
- Hence, its ions move quickest and easily produce energy.
- Lithium is also one of the lightest elements on the table.
- Lithium batteries are lighter than nickel and lead options.
Operating Risks Attached to Lithium-Ion Batteries
Let’s Talk Science works with over fifty-five universities, colleges and research institutes, and over a thousand volunteers. Their experience suggests that, “A typical lithium-ion battery will last two-to-three years before it has to be replaced”. Moreover, “Their production and disposal … has a big impact on the environment”.
In theory, lithium-ion batteries are safe when correctly manufactured. That’s because they have a separator that prevents the electrodes from touching each other and short-circuiting.
If this system fails – whether through manufacturing defect or physical damage – then this can cause, “A huge build-up of heat. If this build-up of heat produces a spark,” Let’s Talk Science continues, “Then the highly flammable electrolyte can catch on fire … and quickly spread to other cells.”
More Information
The Search for Better Lithium Metal Batteries
Steps Toward Safe Lithium Metal Batteries
