Electrochemical performance of LiNi1/3Co1/3Mn1/3O2 cathode recovered from pyrolysis residue of waste Li-ion batteries

Abstract

Cycling performances of lithium-ion batteries using the cathodes of LiNi 1/3 Co 1/3 Mn 1/3 O 2 recovered from pyrolysis residue of a waste automotive lithium-ion battery stack (Recovered NCM111 including impurities), and commercial LiNi 0.5 Co 0.2 Mn 0.3 O 2 (Commercial NCM523). • A bare waste Li-ion battery stack was pyrolyzed at 800 °C under air-free conditions. • LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathode was hydrometallurgically recovered from pyrolyzed stack. • The cathode included Al, Cu, and Fe impurities at a total of 4 mass% and residual F. • Cathode exhibited a specific capacity of 120 mAh g −1 and very high cycling stability. • High-level coexistence of Al, Cu, and Fe was not harmful to the recovered cathodes. A methodology for time-effective, automatic, and safe extraction of cathode active materials from waste lithium-ion battery (LIB) stacks without complex mechanical disassembly and using electrically and chemically harmless processes can be beneficial for the sustainable fabrication of LIB. Herein, we present a feasibility study on the recovery of ternary Li transition metal oxide (LTMO) cathode active materials from the residue of a waste automotive LIB stack using pyrolysis at 800 °C without exposure to air. Sequential processes from pyrolysis, residue grinding, classification (sieving), wet magnetic separation, acid leaching, hydroxide precipitation, and desalination to drying were used to prepare the precursor of the cathode active material. The precursor was mixed with Li 2 CO 3 and sintered in air at 800 °C, which yielded LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM) with metallic impurities of Al, Cu, and Fe at a total of 4 mass% as well as excess Li and residual F. The electrochemical performance of waste LIB-derived LiNi 1/3 Co 1/3 Mn 1/3 O 2 (W-NCM) cathode active materials was evaluated in half-cell and full-cell configurations and compared with that of a commercial LIB cathode active material of LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM) used in automobile applications. The Li-ion extraction/insertion specific capacity of W-NCM in the half-cell was 120 mAh/g at 15 mA g −1 , which was 70.4 % that of NCM. The specific capacity of W-NCM in a full-cell using a graphite anode at 0.1 C was 85 mAh/g, which was 69.1 % that of NCM. However, W-NCM in the full-cell exhibited much higher capacity retention (91.2 %) after 1000 charge–discharge cycles at 2 C, while the capacity retention of NCM was 34.0 %. The excellent cycling performance of W-NCM was attributed to the co-existence of metallic impurities. The proposed cathode recovery method may be further explored for applications in large-scale and automatic recycling of waste LIBs.