Maximizing energy utilization and lithium leaching efficiency via sequential electrochemical dual-oxidation and...

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Chemistry

Background:

• Escalating global demand for lithium necessitates efficient recycling of spent lithium-ion batteries.
• Current lithium leaching methods often have high energy consumption and environmental impact.
• Spent ternary lithium-ion battery cathodes (e.g., NCM) are a critical resource for lithium recovery.

Purpose of the Study:

• To develop an energy-effective two-stage continuous oxidation method for lithium leaching from spent NCM cathodes.
• To optimize electric energy consumption in the electrochemical dual-oxidation (EDO) process.
• To elucidate the mechanism of lithium leaching and energy reduction.

Main Methods:

• Proposed a two-stage continuous oxidation method: electrochemical dual-oxidation (EDO) followed by soaking relaxation.
• Applied the method to commercial and spent LiNi_1/3Co_1/3Mn_1/3O₂ (NCM111) cathodes.
• Conducted comprehensive mechanism studies on lattice oxygen transformation and electrical energy profiles.

Main Results:

• Achieved high lithium leaching efficiencies: 99.87% for commercial NCM111 and 98.12% for spent NCM111.
• Demonstrated a 49.78% reduction in electric energy consumption compared to conventional methods.
• Revealed that EDO induces lattice oxygen transformation, facilitating continuous lithium leaching.

Conclusions:

• The proposed two-stage EDO method is highly effective and energy-efficient for lithium recovery from spent NCM batteries.
• The mechanism involving lattice oxygen transformation is key to the enhanced leaching efficiency and reduced energy consumption.
• This approach offers a sustainable pathway for the industrial recovery of critical metals from lithium-ion battery waste.