Upcycling of Spent Lithium Cobalt Oxide Cathodes from Discarded Lithium-Ion Batteries as Solid Lubricant Additive

This work provides an alternative solution to the challenge of battery recycling via the upcycling of spent lithium cobalt oxide (LCO) as a new promising solid lubricant additive. An advanced solid lubricant mixture of graphene, Aremco binder, and recycled LCO was formulated into a spray with the use of excess volatile organic solvent. Numerous flat steel disks were spray-coated with the new lubricant formulation and naturally dried followed by curing at 180 °C. When tested on a ball-on-disk up to 230 m in distance, the composite new solid lubricant reduced the coefficient of friction (COF) by 85% between two steel surfaces compared to unlubricated surfaces under a constant 1 GPa Hertzian pressure in an ambient environment. The tribofilm composition, particle size, and type of contact are identified as important parameters in the improvement of the COF. Scanning electron microscopy was used to study its morphology, and energy dispersive X-ray spectroscopy was used to analyze the composition of pristine and tested tribofilms. Upcycled spent low value LCO powder was used as a lubricant additive in tribology for the first time with exceptional lubricious properties.