Reductive Thermal Treatment of LiCoO₂ from End-of-Life Lithium-Ion Batteries with Hydrogen

Abstract

Reductive thermal treatment of lithium-ion battery (LIB) cathode material (LiCoO2) by H2 was investigated as an environmentally benign LIB recycling process. Thermogravimetric analysis of recovered LiCoO2 cathode material showed that complete reduction of LiCoO2 to Li compounds and Co by H2 took place at a lower temperature compared to that by carbothermal reduction with graphite in N2 atmosphere. Thermal reduction at 600 °C with 5% H2 demonstrated the conversion of LiCoO2 to Co and Li2O in 120 min. These compounds were successfully separated by water leaching and wet-magnetic separation. During reduction with H2 in the presence of carbon, Li2CO3 was found to form, indicating that the complete removal of carbon is necessary to produce LiOH. The activation energy for thermal reduction with hydrogen was determined by model-free kinetic analysis. In comparison with carbothermal reduction, thermal reduction using hydrogen results in a 65% decrease in activation energy.

Direct Reuse of Spent Lithium-Ion Batteries as an Efficient Heterogeneous Catalyst for the Reductive Upgrading of Biomass-Derived Furfural

“…As expected, the diffraction peaks of LiMeO 2 disappear after the reductive treatment at 500 °C in favor of the formation of metallic Co and Ni as well as Li 2 O, whereas the formation of metallic Mn and Li from the corresponding oxides requires higher temperatures , as a result of the following reactions:…”

“…The TGA-DTA analysis was used to study the thermal behavior of BM. Figure S1 shows a gradual weight loss of BM until 600 °C that can be attributed to the decomposition of the (residual) polymer binder and the graphitic carbon . The thermal analysis highlights how the BM is unstable at temperatures in the range of 600–750 °C.…”

Vacuum Pyrolysis of Pine Sawdust to Recover Spent Lithium Ion Batteries: The Synergistic Effect of Carbothermic Reduction and Pyrolysis Gas Reduction

“…During the pyrolysis of PS, not only CO, CH 4 , and other pyrolysis gas will be produced but also biochar will be generated. These gaseous products could reduce LiCoO 2 to CoO (eqs and ), as reported in past studies . The reduction of LiCoO 2 by C (eq ) likely occurred above 973 K in N 2 . …”

“…The current medium-temperature pyrometallurgical recovery method is mainly about the carbon-based carbothermic reduction process. − Recently, Xiao et al developed a vacuum organic pyrolysis route to recover LiCoO 2 , LiMn 2 O 4 and LiCo x Mn y Ni z O 2 in the forms of Li 2 CO 3 and Li 2 O from 973 to 1273 K. Zhang et al mixed lignites and spent lithium, cobalt, manganese (NCM) battery cathode materials and selectively extracted more than 85 wt % of lithium with a low L/S ratio by carbonization and leaching. Pinegar et al used H 2 as a reducing agent to reduce LiCoO 2 to Co. Compared with carbothermal reduction, the use of H 2 reduced the reduction time and achieved a lower temperature of 873 K. Thus, the thermal reduction processes mainly use carbon and hydrogen and their compounds. − In addition, various organisms (biomass) formed through photosynthesis are carriers of carbon and hydrogen. − In 2019, 5.1% of the total global energy demand is the development and utilization of biomass energy, which accounts for about 50% of all renewable energy consumption, estimated at 19.5 EJ. , Zhao et al used microwave heating and biomass pyrolysis to reduce Li­(Ni 1/3 Co 1/3 Mn 1/3 )­O 2 to water-soluble Li 2 CO 3 with a Li recovery rate of 93.4% .…”

“…36−39 Recently, Xiao et al 13 developed a vacuum organic pyrolysis route to recover LiCoO 2 , LiMn 2 O 4 and LiCo x Mn y Ni z O 2 in the forms of Li 2 CO 3 and Li 2 O from 973 to 1273 K. Zhang et al 40 mixed lignites and spent lithium, cobalt, manganese (NCM) battery cathode materials and selectively extracted more than 85 wt % of lithium with a low L/S ratio by carbonization and leaching. Pinegar et al 41 used H 2 as a reducing agent to reduce LiCoO 2 to Co. Compared with carbothermal reduction, the use of H 2 reduced the reduction time and achieved a lower temperature of 873 K. Thus, the thermal reduction processes mainly use carbon and hydrogen and their compounds.…”