Hydrometallurgical Strategy To Reduce Waste through the Recycling of Lithium Iron Phosphate Batteries

Abstract

Batteries with LiFePO₄ as active material stand out due to the absence of critical materials, such as nickel and cobalt, thermal stability, and security. In the next years, high volumes of LFP batteries will reach their end of life, and overall material recovery will contribute to meeting the Li demand and reducing the CO₂ footprint. Recovery of 97% of plastics and 85.3% graphite prevented materials from burning in furnaces and reduced the CO₂ footprint from recycling. Leaching cathode active material using H₂SO₄ without H₂O₂ resulted in active material leaching with reduced metallic foil solubilization and less reagent consumption. Redirecting H₂O₂ consumption to Fe removal by precipitation, combined with ion exchange columns at 25 °C, successfully deepened Fe purification from solution. Precipitation of Al recovered 15.3% as an Al-(OH)₃ coproduct. After evaporation in a real solution, 72.2% of Li was precipitated as Li₂CO₃, contributing to increasing the recycling share in the Li supply.

1

Leaching efficiencies of Fe, Li, and Al, varying the (A) S/L ratio with the conditions H₂SO₄ = 1.5 mol/L and T = 90 °C, (B) H₂SO₄ concentration with the conditions S/L ratio = 1/5 and T = 90 °C, and (C) temperature with the conditions S/L ratio = 1/5 and H₂SO₄ = 1 mol/L.

2

Mass balance for Li, Fe, C, Cu, and Al in the overall steps for hydrometallurgical recycling. The flowchart indicates the mass percentages of each material outlet streams. Percentages of Al, Cu, C, Li, and Fe are expressed relative to the total element mass. Each green label indicates the recovery values obtained during the LFP recycling process.

3

Pourbaix diagrams for the (A) Li–Fe–P–H₂O 25 °C and (B) Al–P–H₂O systems at 25 °C, illustrating the predominant species (Simulated with Hydra-Medusa).

4

Schematic of the ion exchange system. “Inlet” indicates the battery leachate fed to the fixed-bed column; “outlet (raffinate)” denotes Fe-depleted solution; flow direction and bed volume are indicated.