Closing the Loop on Lithium-Ion Battery Cathodes: A Green Electrometallurgical Recycling Approach

Abstract

The burgeoning use of lithium-ion batteries (LIBs) creates a growing challenge: spent battery management. Traditional hydrometallurgical recycling with coprecipitation generates massive Na₂SO₄ wastewater, posing a significant environmental burden. This work presents a novel, closed-loop recycling method for LIB cathode materials that merges electrolysis and hydrometallurgy. Using Na₂SO₄ electrolysis, we produced high-purity sulfuric acid and sodium hydroxide solutions, which served as the key reagents for leaching and resynthesizing waste cathodes. Optimized leaching conditions ensure near-complete recovery of valuable metals. Li₂CO₃ and a precursor (Ni_0.8Co_0.1Mn_0.1(OH)₂) are subsequently precipitated and regenerated into a new LiNi_0.8Co_0.1Mn_0.1O₂ cathode material, which demonstrates excellent electrochemical performance. The spent Na₂SO₄ solution undergoes a simple treatment before re-electrolysis, achieving a closed-loop system with minimal waste generation and reduced reliance on external reagents. Moreover, the acid-leaching carbon residue is repurposed as a bifunctional carbon-based catalyst for hydrogen peroxide production. This innovative approach offers both economic and environmental benefits, paving the way for sustainable LIBs recycling and a circular economy for battery materials.