A Green and Ingenious Process for Stripping Cathode Materials from Spent Lithium Iron Phosphate Batteries

Abstract

Lithium iron phosphate (LFP) batteries are increasing rapidly in new energy vehicles for their superiorities in cost and cycling performance. This study developed a green process for separating cathode materials from aluminum foil of spent LFP batteries. The process ingenious applied the chemical properties of LFP battery cathode materials, in which only green hydrogen peroxide was utilized or electrolysis method was applied to induce slight in-situ Fenton reaction, achieving complete stripping of cathode materials with a flawless Al foil. The core mechanisms of both methods were to generate hydroxyl radicals in the stripping system. Hydroxyl radicals could not only oxidize PVDF, but also reduce the binding energy between PVDF and Al foil, weaken the adhesion between Al foil and the cathode materials, and accelerated the stripping effect. The morphology and crystal structure of the stripped lithium iron phosphate cathode materials were intact, and Al foil had a smooth surface with extreme less dissolution rate (<0.4%). In addition, economic analysis showed that this stripping process was profitable. Therefore, this study provided an economical and green recovering approach for spent lithium iron phosphate batteries.

Keywords: New energy vehicles, Spent Lithium iron phosphate batteries, cathode materials, Fenton reaction, Stripping