Role of impurity copper in Li-ion battery recycling to LiCoO2 cathode materials

ACS Sustainable Chem. Eng.

Zheng

Yao

et al. 2020

Many recycling processes have been developed for spent Li-ion batteries (LIBs), such as pyrometallurgy, hydrometallurgy, and direct recycling. For all the recycling methods, however, impurities are always introduced from the current collectors or casing materials, especially aluminum (Al), which might lead to negative effects on recovered electrode materials. Therefore, it is significant to determine the impacts of Al impurity on recovered materials. Here, the influence of the Al impurity for the synthesized LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) precursor and cathode is systematically studied. The cell with 0.2 at % Al impurity displays the highest reversible capacities (145.2, 130.5, and 100.3 mAh g −1 from 2, 3, and 5 C, respectively) and striking cycling capability at 2 C after 100 cycles with the highest retention capacity of 138.5 mAh g −1 . Meanwhile, the excess Al ions (5 at %) lead to the Li/Mn superlattice structure and deteriorate electrochemical performance of the synthesized NCM622 cathode.

Section: Introductionmentioning

confidence: 99%

Systematic Study of Al Impurity for NCM622 Cathode Materials

ACS Sustainable Chem. Eng.

Zheng

Yao

et al. 2020

“…Wet comminution prevents overcrushing that leads to fine particles of current collectors and achieves liberation of coatings from foils with fewer Cu, Al, and polymer materials in the fine fractions . It is known that electrode material is highly sensitive to contamination by other metals, such as aluminum, which results in unfavorable properties . More elaborate and milder methods for LIB dismantling deserve to be further explored.…”

Section: Pretreatment Of Spent Libsmentioning

confidence: 99%

Sustainable Recycling of Electrode Materials in Spent Li-Ion Batteries through Direct Regeneration Processes

Peng

2022

ACS EST Eng.

The prevalence of electric vehicles (EVs) globally could generate a huge number of spent Li-ion batteries (LIBs) as they reach their end of life. It is expected that by 2030, 11 million metric tons of EOL LIBs will be generated cumulatively, with annual waste flows of EV batteries reaching 34,000 t by 2040. Recycling spent LIBs in a sustainable and effective manner is a matter of utmost importance. Conventional recycling strategies such as pyrometallurgy and hydrometallurgy decompose the crystal structures of value-added electrode materials to element levels, presenting fatal drawbacks in high greenhouse gas emissions, cost, and energy consumption. The burgeoning direct recycling processes provide viable options to rejuvenate LIB compounds without chemical change, thus retaining their original composition as well as the embedded energy. Relithiation and defect restoration are the critical steps for electrode regeneration, which determine the performance of recovered material. Here, the authors provide a detailed discussion and analysis on different regeneration methods for LIB electrodes based on their degradation mechanisms. The advancements of direct recycling among other recycling technologies are highlighted through discussions of its process benefits. Physical pretreatments including deactivation, disassembly, and black mass separation are introduced. Perspectives toward scaled applications of direct recycling are also demonstrated on the basis of developing trends of future LIBs.

“…%) could lead to the impurity phase and deteriorate the electrochemical performance of recovered cathodes. For Cu impurities, their effects on recovered LiCoO 2 and NCM111 cathode materials have been widely studied and these findings highlight that Cu impurities exhibited positive impacts toward electrochemical performance of recovered cathodes on trace amounts, while excessive Cu impurities could decline the cathode electrochemical properties. − Our group systematically studied the impacts of Cu impurities with ionic and metal forms toward the recovered NCM622 cathodes, which was proved that Cu metal should be entirely removed during recycling, while the ionic Cu impurity might be regarded as a favorable dopant with certain amounts (0.34 and 0.10 at. %) toward recovered NCM622 cathodes .…”

Section: Introductionmentioning

confidence: 99%

Valence Effects of Fe Impurity for Recovered LiNi_0.6Co_0.2Mn_0.2O₂ Cathode Materials

ACS Appl. Energy Mater.

Zheng

Vanaphuti

et al. 2021

Iron impurities are generally included in the obtained leaching liquor solution during the hydrometallurgical recycling method of spent lithium-ion batteries (LIBs) due to the usage of iron in battery casings and machinery parts of recycling equipment, which would definitely affect the physical and electrochemical features of the recovered active materials. In this work, the effects of iron impurity with different valence states (Fe2+ and Fe3+) and gradient concentrations (0.2, 1.0, and 5.0 at. %) for the obtained LiNi0.6Co0.2Mn0.2O2 (NCM622) cathodes are fully studied. It is found that Fe3+ impurity could easily lower the tap density and average size of NCM622 particles and even introduce some impurity phases in the NCM622 structure at high concentration (5.0 at. %), leading to much lower specific capacity, worse rate capability, and cycling performance of the Fe3+-based NCM622 cathode. On contrast, with certain concentrations of Fe2+ impurity (0.2 and 1.0 at. %), the NCM622 cathode material exhibits comparable and much better electrochemical properties compared with the virgin NCM622 materials. Based on these results, the valence of Fe impurity should be considered and controlled as well as its concentration during the recycling process design for spent LIBs.