Hydrogen reduction of spent lithium-ion battery cathode material for metal recovery: Mechanism and kinetics

Thermodynamic possibilities and constraints for pure hydrogen production by a nickel and cobalt-based chemical looping process at lower temperatures

Single (Iron) and Binary (Iron and Cobalt) Metal Oxide Doped Silica Membranes for Gas Separation

The reduction of chromium, nickel, and manganese oxides by hydrogen, CO, CH4, and model syngas (mixtures of CO + H2 or H2 + CO + CO2) and oxidation by water vapor has been studied from the thermodynamic and chemical equilibrium point of view. Attention was concentrated not only on the convenient conditions for reduction of the relevant oxides to metals or lower oxides at temperatures in the range 400–1000 K, but also on the possible formation of soot, carbides, and carbonates as precursors for the carbon monoxide and carbon dioxide formation in the steam oxidation step. Reduction of very stable Cr2O3 to metallic Cr by hydrogen or CO at temperatures of 400–1000 K is thermodynamically excluded. Reduction of nickel oxide (NiO) and manganese oxide (Mn3O4) by hydrogen or CO at such temperatures is feasible. The oxidation of MnO and Ni by steam and simultaneous production of hydrogen at temperatures between 400 and 1000 K is a difficult step from the thermodynamics viewpoint. Assuming the Ni—NiO system, the formation of nickel aluminum spinel could be used to increase the equilibrium hydrogen yield, thus, enabling the hydrogen production via looping redox process. The equilibrium hydrogen yield under the conditions of steam oxidation of the Ni—NiO system is, however, substantially lower than that for the Fe—Fe3O4 system. The system comprising nickel ferrite seems to be unsuitable for cyclic redox processes. Under strongly reducing conditions, at high CO concentrations/partial pressures, formation of nickel carbide (Ni3C) is thermodynamically favored. Pressurized conditions during the reduction step with CO/CO2 containing gases enhance the formation of soot and carbon-containing compounds such as carbides and/or carbonates.

Reduction of nickel(II) oxide with hydrogen and deuterium has been followed in the temperature interval 240-440°C. In the range of lower temperatures and in the initial stage of the reaction an inversion isotopic effect takes place which changes, with increasing degree of reduction and with increasing temperature, into a normal isotopic effect. The kinetics of reduction both with hydrogen and with deuterium can be quantitatively described by two different relations, ac­ cording to the degree of reduction. The values of the apparent activation energy and the changes in the kinetics of reduction, when catalyzed by addition of Pd, in dependence on the reducing medium, allow to estimate the conditions under which the rate-determining step are the internal transport processes. The isotopic effect, characterizing the region of high reduction degree and the region of higher temperatures, is due to diffusion, either of molecular hydrogen, or, in the presence of a catalyst, of the activated hydrogen, to the reaction interface.

Confinement tests are implemented for measuring exothermic behaviors of eight delithiated or non-lithiated cathode materials mixed with ethylene carbonate (EC) which are commonly used in lithium-ion batteries. Eight delithiated and non-lithiated cathode materials, namely lithium cobalt oxide (LixCoO2), nickel oxide (NiO2), lithium nickel oxide (LixNiO2), lithium nickel cobalt oxide (LixNi0.8Co0.2O2), manganese oxide (Mn2O4), lithium manganese oxide (LixMn2O4), cobalt oxide (Co3O4) and iron phosphate (FePO4)are mixed with EC under a programmed rate of heating, respectively. Trajectories of temperature and pressure are measured simultaneously in the confined apparatus. Characteristics of thermal runaway such as onset temperature, maximum temperature, maximum pressure, maximum self-heat rate, etc., are assessed. The ranking of thermal stabilities of delithiated cathode and non-lithiated materials with EC is discussed and compared.

Effect of graphite on selective lithium recovery from NCM-lithium battery black mass via hydrogen reduction.

Effects of microwave irradiation on the electrochemical performance of manganese-based cathode materials for lithium-ion batteries

Chapter 27 - Hydrogen Reduction of Nickel from Ammoniacal Sulfate Solutions

Consecutive engineering of anodic graphene supported cobalt monoxide composite and cathodic nanosized lithium cobalt oxide materials with improved lithium-ion storage performances

An effective process for the recovery of valuable metals from cathode material of lithium-ion batteries by mechanochemical reduction

Improving soldier portable power systems is very important for saving soldiers' lives and having a strategic advantage in a war. This paper reports our work on synthesizing lithium vanadium oxides (Li_1+xV₃O₈) and developing their applications as the cathode (positive) materials in lithium-ion batteries for soldier portable power systems. Two synthesizing methods, solid-state reaction method and sol-gel method, are used in synthesizing lithium vanadium oxides, and the chemical reaction conditions are determined mainly based on thermogravimetric and differential thermogravimetric (TG-DTG) analysis. The synthesized lithium vanadium oxides are used as the active positive materials in the cathodes of prototype lithium-ion batteries. By using the new solid-state reaction technique proposed in this paper, lithium vanadium oxides can be synthesized at a lower temperature and in a shorter time, and the synthesized lithium vanadium oxide powders exhibit good crystal structures and good electrochemical properties. In the sol-gel method, different lithium source materials are used, and it is found that lithium nitrate (LiNO₃) is better than lithium carbonate (Li₂CO₃) and lithium hydroxide (LiOH). The lithium vanadium oxides synthesized in this work have high specific charge and discharge capacities, which are helpful for reducing the sizes and weights, or increasing the power capacities, of soldier portable power systems.

Commonly, studies of lithium ion battery (LIB) cathode materials are performed by using lithium metal anode and olefin-based microporous separator. On the other hand, carbon-based anodes and various separators are used in commercial lithium ion batteries. In this work, we studied characteristics of a solid solution cathode material 0.4Li2MnO3-0.6LiMn1/3Ni1/3Co1/3O2, using graphite as the anode and influence of separator type on structural change of the cathode material was studied.0.4Li2MnO3-0.6LiMn1/3Ni1/3Co1/3O2 was synthesized by co-precipitation method. The obtained material was characterized by XRD and ICP-AES. The XRD data showed that all major peaks of the synthesized material can be assigned to monoclinic C2/m. We combined three types of separators, polypropylene microporous membranes, OZ-S25 (ceramic coated PET nonwoven) and FPC3012 (nonwoven composed of PET and cellulose) with this anode and cathode.The charge-discharge cycle tests were performed in a bipolar cell using graphite as the anode. When the cathode material was combined with graphite anode, abnormally fast deterioration of cell capacity was observed. To avoid the deterioration, the graphite anode was preprocessed by charging and discharging using lithium metal as the counter electrode. The effect of the preprocess was sufficient only when the Li amount contained in the anode corresponds to at least 10% of the fully charged state. The preprocess could be achieved also by using LiMn1/3Ni1/3Co1/3O2 as the counter electrode. The reason of this improvement is unclear, but SEI formation on graphite anode surface, Li insertion into graphite, or drop in the anode potential might be the reason.Charging and discharging were performed for 5 cycles at 0.1C and 50 cycles at 1C in the voltage range of 2.0 to 4.7 V vs. preprocessed graphite using the various separators above. The figure shows charge and discharge curve for 0.4Li2MnO3-0.6LiMn1/3Ni1/3Co1/3O2 and the preprocessed graphite cell (separator: OZ-S25). The preprocess of the graphite anode stabilized the cell capacity. After the 5th and 55th discharge, the cathode materials were taken out and the average structure was examined by Rietveld method using neutron diffraction measurements at BL20, J-PARC and synchrotron X-ray diffraction measurement at BL19B2, Spring-8. Furthermore, the valence of transition metals after cycle tests was evaluated on XAFS at BL14B2, SPring-8. As a result, with all separators, it was found that the Ni occupancy of the 4g sites, a transition metal layer, decreased, and that of 2c sites, a Li layer, increased. It was also found that the valence of the transition metal after 5 cycles did not differ between the separators. On the other hand, the bond valence sum at each site tended to decrease at the 4g sites and the 2c sites and increase at the 2b sites after 5 cycles. These were the same regardless of the type of the anode, metallic lithium or graphite. It was found that the average crystal structure of the solid solution cathode after 5 cycles was independent from the separator type and the anode type. The result after 55th discharge will be reported on the presentation. Figure 1

In order to satisfy the rapidly increasing demands for a large variety of applications, there has been a strong desire for low-cost and high-energy lithium-ion batteries and thus for next-generation cathode materials having low cost yet high capacity. In this regard, the research of cobalt (Co)-free and nickel (Ni)-rich (CFNR) layered oxide cathode materials, able to meet the low-cost and high-capacity requirements, has been extensively pursued but remains challenging largely due to the elimination of Co and high content of Ni in these materials. Herein, we systematically review the challenges and recent advances of CFNR cathode materials on these important aspects. Specifically, we first clarify the role of Co in Ni-rich layered oxides and the possibility of its elimination to fabricate CFNR cathode materials. We then discuss the methods developed to synthesize these cathode materials. This is followed by the elucidation about their degradation mechanisms and the research progress of modification strategies achieved in enhancing the properties for these materials. Finally, we discuss the current challenges and future prospects of CFNR cathode materials as the next-generation cathode materials for low-cost and high-energy lithium-ion batteries.

Mechanism of carbothermal reduction of iron, cobalt, nickel and copper oxides

Li-rich layered oxide cathode materials have become one of the most promising cathode materials for high specific energy lithium-ion batteries owning to its high theoretical specific capacity, low cost, high operating voltage and environmental friendliness. Yet they suffer from severe capacity and voltage attenuation during prolong cycling, which blocks their commercial application. To clarify these causes, we synthesize Li1.5Mn0.55Ni0.4Co0.05O2.5 (Li1.2Mn0.44Ni0.32Co0.04O2) with high-nickel-content cathode material by a solid-sate complexation method, and it manifests a lot slower capacity and voltage attenuation during prolong cycling compared to Li1.5Mn0.66Ni0.17Co0.17O2.5 (Li1.2Mn0.54Ni0.13Co0.13O2) and Li1.5Mn0.65Ni0.25Co0.1O2.5 (Li1.2Mn0.52Ni0.2Co0.08O2) cathode materials. The capacity retention at 1 C after 100 cycles reaches to 87.5% and the voltage attenuation after 100 cycles is only 0.460 V. Combining X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscopy (TEM), it indicates that increasing the nickel content not only stabilizes the structure but also alleviates the attenuation of capacity and voltage. Therefore, it provides a new idea for designing of Li-rich layered oxide cathode materials that suppress voltage and capacity attenuation.