Engineering
Recycling Lithium-Ion Batteries to Recover Cobalt and Lithium
Quick fact
Recycling a kilogram of lithium-ion battery cathodes can recover approximately 0.5 kg of cobalt and 0.15 kg of lithium, enough to offset the environmental impact of mining new metals by up to 60%.
Why this is interesting
You probably know that your phone battery is recyclable, but did you know that without recycling, we might run out of cobalt and lithium in a few decades?
Read the full explanation
Understanding Recycling Lithium-Ion Batteries to Recover Cobalt and Lithium
When a lithium-ion battery is used, lithium ions move between the anode and cathode. In the cathode, cobalt and lithium are locked in a layered oxide (like LiCoO₂). To recover these metals, we first dismantle the battery and separate the black mass—the crushed mix of cathode and anode materials. Then we use either heat or chemical leaching to dissolve the metals, and finally we selectively precipitate or extract them as pure chemical compounds. The hydrometallurgical route, which uses acids and solvents, is more common because it can achieve high recovery rates and works at lower temperatures.
A deeper explanation
The fundamental challenge in lithium-ion battery recycling is separating and reclaiming metals that are chemically bound in a complex cathode structure. Pyrometallurgy, the traditional smelting route, heats the entire battery to 1000°C, which recovers cobalt and nickel as an alloy, but lithium goes into the slag and is lost. Hydrometallurgy, on the other hand, grinds the black mass, then leaches it with acid (e.g., sulfuric acid and hydrogen peroxide) to dissolve metals into solution. Using solvent extraction—mixing in an organic chemical that selectively binds cobalt—and then stripping with a second acid, we can obtain pure cobalt sulfate. Lithium remains in the aqueous solution but is often costlier to extract; adding sodium carbonate precipitates lithium carbonate. The efficiency of recovery depends on the selectivity of each step, which is why modern facilities often integrate mechanical pre-processing to enrich the cathode material before chemical treatment.