(536g) Synthesis of Nanostructured Cobalt Oxide Rods from Waste Lithium-Ion Batteries

Cobalt oxide (Co₃O₄) is an important p-type semiconductor with spinel structure that has applications in various fields such as catalysis, solid-state electronics, and electrochemical devices. Porous Co₃O₄ nanostructures are used as one of the cathode material components in lithium-ion batteries (LiBs). These 1-D cathode structures provide a higher surface area and shorter path length for lithiumions which leads to better electrochemical performance in LiBs. In this work, a novel synthesis process has been developed for producing porous Co₃O₄ nanorods from waste LiB cathodes. The recycling process involves metal separation and recovery from lithium cobalt oxidecathodes using oxalic acid. This process directly separates lithium and cobalt by precipitating cobalt in the form of cobalt oxalate and lithium remains in solution. Addition of hydrogen peroxide as a reducing agent during metal recovery improves metal extraction efficiency and also leads to the formation of rod-shaped cobalt oxalate nanostructures. These cobalt oxalate rods can be converted to porous rods by thermal treatment under appropriate conditions. This presentation will describe the experimental and mechanistic details of the cobalt oxide nanorod synthesis process.