Improved recovery of lithium from spent lithium-ion batteries by reduction roasting and NaHCO3 leaching.

Lithium supply risk is increasing and driving rapid progress in lithium recovery schemes from spent lithium-ion batteries (LIBs). In this study, a facile recycling process consisting mainly of reduction roasting and NaHCO3 leaching was adopted to improve lithium recovery. The Li of spent LiNixCoyMn1-x-yO2 powder were converted to Li2CO3 and LiAlO2 with the reduction effect of C and residual Al in the roasting process. NaHCO3 leaching was utilized to selectively dissolve lithium from Li2CO3 and water-insoluble LiAlO2. The activation energy of NaHCO3 leaching was 9.31 kJ∙mol-1 and the leaching of lithium was a diffusion control reaction. More than 95.19 % lithium was leached and recovered as a Li2CO3 product with a purity of 99.80 %. Thus, this approach provides a green path to selective recovery of lithium with good economics.

Selective recovery of lithium and iron phosphate/carbon from spent lithium iron phosphate cathode material by anionic membrane slurry electrolysis.

A simple, green and effective method, which combined lithium iron phosphate battery charging mechanism and slurry electrolysis process, is proposed for recycling spent lithium iron phosphate. Li and FePO4 can be separation in anionic membrane slurry electrolysis without the addition of chemical reagent. The leaching efficiency of Li can reach to 98% and over 96% of Fe are recycled as FePO4/C. Kinetics analysis indicates that the surface chemical reaction is the control step during the slurry electrolysis. Additionally, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Electrochemical Impedance Spectroscopy (EIS) characterization and thermodynamic analysis are employed to investigate the leaching mechanism. It is found that the spent LiFePO4 is delithiated and oxidized to FePO4 by the function of e-, which is similar as the LiFePO4 battery charging process. EIS analysis also verify the kinetics results, the charge transfer resistance controlled the leaching process. Finally, a novel process for recovery of spent LiFePO4 is proposed. The recovered Li2CO3 and FePO4/C can be used for resynthesize LiFePO4, and the resynthesized LiFePO4 exhibits reversible capacities of 143.6 mAh g-1 at 1C and high current efficiency, stable cycle performances at 0.1 and 0.5C which meets the basic requirements for reuse.