TY - JOUR
T1 - Glycine-Assisted Hydrothermal Leaching of LiCoO2/LiNiO2Cathode Materials with High Efficiency and Negligible Acid Corrosion Employing Batch and Continuous Flow System
AU - Zheng, Qingxin
AU - Shibazaki, Kensuke
AU - Hirama, Seiya
AU - Iwatate, Yuta
AU - Kishita, Atsushi
AU - Hiraga, Yuya
AU - Nakayasu, Yuta
AU - Watanabe, Masaru
N1 - Funding Information:
This work was supported by the Japan Science and Technology Agency (JST)-Mirai program [grant no. JP18077450] and the Japan Society for the Promotion of Science (JSPS)-Grant-in-Aid for Challenging Exploratory Research [grant no. 18K18966].
Publisher Copyright:
©
PY - 2021/3/1
Y1 - 2021/3/1
N2 - Glycine was applied as the leachant for the hydrothermal leaching of lithium-ion battery (LIB) cathode materials, LiCoO2 and LiNiO2, at 90-180 °C for 5-90 min. LiCoO2 was completely leached at 180 °C for 30 min. It was revealed that Co(III)-glycine complex formed first and was gradually reduced to Co(II)-glycine complex. Compared to LiCoO2, LiNiO2 required a lower temperature and shorter time for complete leaching. Different from using inorganic acids or organic acids like citric acid, pH values of the glycine solution before or after hydrothermal leaching of LiCoO2 or LiNiO2 was in the range 5.8-9.0, closer to neutral. In the mechanism analysis, the consumption of glycine was attributed to the oxidation of glycine and the formation reaction of Co-glycine complex; during the hydrothermal leaching at 180 °C for 30 min, more than half of leached Co was calculated to be reduced from trivalent to divalent. The shrinking unreacted core model was adopted to study the kinetics. As a result, hydrothermal leaching of Li and Co with glycine was well fitted by the interface reaction control, and the activation energies of Li and Co leaching were 87.5 and 72.2 kJ/mol, respectively. With the successful running of continuous hydrothermal leaching of LiCoO2 with glycine using a specifically customized flow system, LIB cathode materials were leached through the green and continuous process with a high efficiency close to 100%, and the acid corrosion was detected to be as light as to be almost negligible, for the first time.
AB - Glycine was applied as the leachant for the hydrothermal leaching of lithium-ion battery (LIB) cathode materials, LiCoO2 and LiNiO2, at 90-180 °C for 5-90 min. LiCoO2 was completely leached at 180 °C for 30 min. It was revealed that Co(III)-glycine complex formed first and was gradually reduced to Co(II)-glycine complex. Compared to LiCoO2, LiNiO2 required a lower temperature and shorter time for complete leaching. Different from using inorganic acids or organic acids like citric acid, pH values of the glycine solution before or after hydrothermal leaching of LiCoO2 or LiNiO2 was in the range 5.8-9.0, closer to neutral. In the mechanism analysis, the consumption of glycine was attributed to the oxidation of glycine and the formation reaction of Co-glycine complex; during the hydrothermal leaching at 180 °C for 30 min, more than half of leached Co was calculated to be reduced from trivalent to divalent. The shrinking unreacted core model was adopted to study the kinetics. As a result, hydrothermal leaching of Li and Co with glycine was well fitted by the interface reaction control, and the activation energies of Li and Co leaching were 87.5 and 72.2 kJ/mol, respectively. With the successful running of continuous hydrothermal leaching of LiCoO2 with glycine using a specifically customized flow system, LIB cathode materials were leached through the green and continuous process with a high efficiency close to 100%, and the acid corrosion was detected to be as light as to be almost negligible, for the first time.
KW - acid corrosion
KW - continuous leaching
KW - glycine
KW - hydrothermal leaching
KW - lithium-ion battery
KW - shrinking unreacted core model
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U2 - 10.1021/acssuschemeng.0c08703
DO - 10.1021/acssuschemeng.0c08703
M3 - Article
AN - SCOPUS:85101993739
VL - 9
SP - 3246
EP - 3257
JO - ACS Sustainable Chemistry and Engineering
JF - ACS Sustainable Chemistry and Engineering
SN - 2168-0485
IS - 8
ER -