In a study published in Advanced Materials, a research team led by Prof. ZHANG Yunxia from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences developed an integrated bulk and surface commodification strategy to upgrade spent lithium cobalt oxide batteries (S-LCO) to operate at high voltages.
As the demand for high-energy-density storage devices grows, there's a need to find sustainable ways to upgrade old LiCoO2 (LCO) batteries into more stable, high-voltage cathode materials.
In this research, scientists developed an easy and effective method to improve LCO batteries. They used a combination of wet chemical treatment, heating, and a special phosphorus coating technique. This process included adding extra lithium, applying a uniform coating of lithium phosphate/cobalt phosphide (LPO/CP) on the surface, and incorporating manganese into the bulk material, along with a gradient of phosphorus near the surface. These modifications were all achieved simultaneously, resulting in significantly enhanced battery performance.
The result of these modifications is an upgraded LCO cathode, named MP-LCO@LPO/CP, which shows significantly better electrochemical performance. The improved cathode demonstrates high specific capacity and excellent cycling stability.
The team also investigated why the upgraded cathode performs so well at high voltages. They discovered that the modifications enhance both structural stability and electrochemical properties, resulting in improved battery performance.
"This method is simple and easy to scale up, so it could also be used to recycle other waste cathode materials. This approach has great potential for sustainable development in the lithium-ion battery industry," said Prof. ZHANG.
Figure 1. Schematic illustration for the upcycling of S-LCO into MP-LCO@LPO/CP. (Image by LIU Zhenzhen)