The proliferation of electric cars, smartphones, and portable devices is leading to an estimated 25 percent increase globally in the manufacturing of rechargeable batteries each year. Many raw materials used in the batteries, such as cobalt, may soon be in short supply.
Researchers have discovered that electrodes in lithium batteries containing cobalt can be reused as is after being newly saturated with lithium. In comparison to traditional recycling, which typically extracts metals from crushed batteries by melting or dissolving them, the new process saves valuable raw materials as well as energy.
As lithium cobalt oxide batteries age, one of the main causes of battery deterioration is the depletion of lithium in the electrode material. The structures can nevertheless remain relatively stable, so they can be reused.
Rechargeable lithium-ion batteries have two electrodes between which electrically charged particles move. Lithium cobalt oxide is used in one electrode and in most of the batteries, the other is made of carbon and copper. In traditional battery recycling methods, some of batteries’ raw materials are lost and lithium cobalt oxide turns into other cobalt compounds that require a lengthy chemical refinement process to turn them back into electrode material. The new method replenishes the spent lithium in the electrode through an electrolysis process, commonly used in industry, through which the cobalt compound can be directly reused.
The performance of electrodes newly saturated with lithium is almost as good as with those made of new material. With further development, the method would also work on an industrial scale. The researchers will determine if the same method could be used with nickel-based batteries of electric cars.