O2 Material Research Articles

Boosting the electrochemical performance of LiNi0.8Co0.15Al0.05O2 cathode materials in-situ modified with Li1.3Al0.3Ti1.7(PO4)3 fast ion conductor for lithium-ion batteries

In-situ modification with Li1.3Al0.3Ti1.7(PO4)3 (LATP) fast ion conductor powders is introduced to construct the stable structure of LiNi0.8Co0.15Al0.05O2 (NCA) materials, which are characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, energy disperse spectroscope and X-ray photoelectron spectroscope. The results demonstrate that the particle surface of NCA-1.0 is homogeneously wrapped by a LATP coating layer with a thickness of about 200 nm and the value of Ni2+ ions in the Li layer is 1.58% when the optimal doping proportion of the LATP precursor to the NCA precursor is about 1.0 wt %. The coin cell assembled with NCA-1.0 delivers a remarkable discharge specific capacity of 152.4 mAh g−1 with a capacity retention ratio of 89.5% at 2 C after 150 cycles, a favorable rate capacity of 153.2 mAh g−1 at 5 C, and an increased Li+ diffusion coefficient of 6.65 × 10−10 cm2 s−1. Those outstanding electrochemical properties can be attributed to the synergistic effects of the formed LATP coating and Ti4+ doping, indicating that the in-situ modification way is a promising route to enhance the electrochemical properties of Ni-rich materials for lithium-ion batteries.

P2-type Na0.59Co0.20Mn0.77Mo0.03O2 cathode with excellent cycle stability for sodium-ion batteries

Layered P2-type Mn-based material is considered as one of the most promising cathode materials for sodium-ion batteries, but its unsatisfactory cyclic performance is one of the problems that need to be overcome. Here, we used molybdenum doping strategy to synthesize P2-type Na0.59Co0.20Mn0.77Mo0.03O2 material with a hexagonal layer structure as the cathode of sodium-ion batteries through a solid-state reaction route. The maximum discharge capacity of the Mo-doped cathode is 131.9 mAh g−1 with the capacity retention rate of 91.51% after 100 cycles at 0.1 C (1 C = 156 mAh g−1). Optimized Mo doping effectively decreases the charge transfer resistance and the interface resistance of the Na0.59Co0.20Mn0.80O2 cathode at open circuit and after 100 cycles, respectively, and the growth trends of the charge transfer resistance and the interface resistance are obviously slowed down, which is proved that the cycling stability of the pristine cathode is significantly improved by Mo doping. The main reasons are as follows: (1) Mo doping expands the a-axis and shortens the TM–O bond, which enhances the structural stability of the P2-type oxide; (2) Mo doping increases the crystallinity of the pristine and decreases the degree of cation disorder in the P2-type oxide; (3) the bond energy of Mo–O is stronger than that of Mn–O and Co–O, resulting in a more stable structure of the material. The results provide a meaningful reference for improving the cycle stability and kinetic performance of P2-type cathode materials for sodium-ion batteries.

Al-doping induced superior lithium ion storage capability of LiNiO2 spheres

To optimize the performance of LiNiO2 with minimal modification of the pristine structure, a facile solid-state approach, based on the interdiffusion of elements at the solid/solid interface, is developed to achieve uniformly Al-doped LiNiO2 using alumina coated Ni(OH)2 spheres as the precursor. The resulting LiNi0.95Al0.05O2 material exhibits excellent discharge capacity (209.9 mAh g−1 at 0.1 C) and cycling stability with a capacity retention of 85.10% after 200 cycles at 0.5 C. This is ascribed to the improved reversibility of the phase transitions by Al-doping as revealed by in-situ XRD characterization. The Al-doping also endows the material with superior rate capability due to the enlarged interlayer spacing in the structure and alleviation of the side reactions at the electrode/electrolyte interface, favorable for lithium ion diffusion. An optimal amount of doped Al is necessary for ensuring the structure stability and interface ionic conductivity of the LiNiO2 spheres. Thus, the present strategy may provide an opportunity to optimize the performance of LiNiO2, with uniform doping of a small amount of Al, producing a promising cathode material for advanced lithium ion batteries.

Improving electrochemical performances of Lithium-rich oxide by cooperatively doping Cr and coating Li3PO4 as cathode material for Lithium-ion batteries

Lithium-rich layered oxides exhibit one of the highest reversible discharge capacities among cathode materials for lithium-ion batteries. However, their voltage decay and poor cycle stability severely restrict their use as a commercial cathode material. In this work, a novel approach of that combines Cr doping and a Li3PO4 coating was designed to address the problems associated with lithium-rich Li1.2Mn0.54Ni0.13Co0.13O2 materials. The synergistic method not only increases the discharge capacity and cycle stability but also decreases the voltage decay. The 1.0 wt% Li3PO4 coating and 0.08 Cr doping on Li1.2Mn0.54Ni0.13Co0.13O2 cathode shows a capacity retention of 76.5% compared to the 59.0% capacity retention for the pristine electrode after 200 cycles. The initial discharge capacity is also increased from 255.8 mAh·g−1 to 265.2 mAh·g−1. In addition, the discharge voltage decay decreases from 0.84 V to 0.39 V after 200 cycles as a result of the Cr doping and Li3PO4 coating. These enhanced electrochemical properties are attributed to the fact that the Cr doping stabilized the layered structure and inhibited its phase transformation to the spinel phase, and the Li3PO4 coating confined the interfacial side reactions between the electrode and electrolyte. This work may provide a new method to solve the subsistent problems of lithium-rich cathode materials.

Synthesis of Ni-Rich Cathode Material from Maleic Acid-Leachate of Spent Lithium-Ion Batteries

The recycling and reclamation of spent lithium-ion batteries have attracted more and more attention. In the present study, maleic acid was employed to leach spent LiCoO₂ cathode materials. The leachate was then taken to synthesize LiNi₀.₈Co₀.₁Mn₀.₁O₂ materials through a coprecipitation and calcination process, where the leachate dosage was controlled at 0%, 20%, 40%, 60%, 80%, and 100%, separately. The results of X-ray diffraction showed that when leachate dosage was lower than 60%, the crystal structure of the materials was normal. However, when the dosage exceeded 80%, the crystal structure was negatively affected, and Li⁺/Ni²⁺ mixing was aggravated. The morphology of the materials became irregular when leachate dosages were 80% and 100%. Moreover, the ratio of Ni²⁺/Ni³⁺ in the materials increased as the leachate dosage increased. When the leachate dosage was lower than 60%, the electrochemical performance of the materials was reasonable. However, if the dosage exceeded 80%, the discharge specific capacity, cycling stability, and rate stability were significantly decreased, while the irreversibility, polarization, and impedance of the electrodes increased. In conclusion, maleic acid-leachate of spent LiCoO₂ materials can be used to synthesize LiNi₀.₈Co₀.₁Mn₀.₁O₂ materials, only if the leachate dosage is kept lower than 60%.

Nafion‐coated LiNi0.80Co0.15Al0.05O2 (NCA) cathode preparation and its influence on the Li‐ion battery cycle performance

AbstractOne of the main problems of LiNi0.80Co0.15Al0.05O2 (NCA) materials is the side reactions occurring during battery cycling. These side reactions result in capacity fading, which in turn decreases the life span of the battery. Conventionally, for nickel‐rich cathodes, an inorganic layer is used as a protective layer. Applying these layers may require additional complicated steps. To overcome this problem, we focused on coating the NCA electrode with a polymeric ion conductive layer that can easily be applied. For this purpose, using an ion‐conductive polymer is a novel approach. We used Nafion as the protective layer on NCA electrodes. While the Nafion layer can protect the surface against the side reactions, it does not prevent the Li+ ion flow. Following this purpose, we synthesized NCA by a modified co‐precipitation method followed by sintering at 750°C. After the preparation of the NCA cathodes, we coated the surfaces with a more straightforward drip coating. The Nafion‐coated electrodes delivered a superior electrochemical performance with 100% of discharge capacity retention even after 100 cycles at 0.1C. The electrochemical impedance spectroscopy revealed that the Nafion coating could effectively prevent passive layer formation, which causes capacity fading.

Phase and Morphological Studies of LiCo0.3Ni0.3Mn0.3Ti0.1-xSnxO2 Cathode Materials

The substitution of LiCo0.3Ni0.3Mn0.3Ti0.1O2 materials with Sn is done to investigate the effect on the phase and morphology. The materials were synthesized via a combustion method. The annealing temperature and time of the precursors was obtained at 700 °C for 24 hours. The crystalline phase and purity of the materials are studied using X-Ray Powder Diffraction (XRPD). All the materials were observed to be pure phase and good cation ordering. Field Emission Scanning Electron Microscope (FESEM) is used to assess the morphology and the crystallites size of the materials. The images showed that the materials consist of polyhedral shaped crystals and well-crystallized particles with smooth surfaces. The % calculated synthesized materials shows close stoichiometry to the % element content from the EDX measurements of the synthesized materials within experimental error.

Al doped LiNi0.6Co0.3-xTi0.1AlxO2 cathode material via combustion method

Aluminium (Al) was doped into cobalt sites of LiNi0.6Co0.3Ti0.1O2 (LNCT) material, producing LiNi0.6Co0.29Ti0.1Al0.01O2, LiNi0.6Co0.27Ti0.1Al0.03O2 and LiNi0.6Co0.25Ti0.1Al0.05O2 cathode materials denoted as LCA1, LCA3 and LCA5 respectively. The synthesis of those materials were using self-propagating combustion method. The doping of Al is done to reduce the toxicity of Co element and to stabilize the cathode structure in order to increase the initial discharged capacity of the lithium-ion battery system. The characterization of the materials was done by using X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). Based on the XRD results, all materials showed a single phase structure. Meanwhile, FESEM results revealed that all materials are polyhedral like shape but the Al doped materials have smaller crystallite size than the undoped material. The electrochemical performance of the battery system using the synthesized cathode were tested. According to the battery testing results, the initial discharged capacity of the Al doped battery were successfully increased.

Synthesis and Performance Evaluation of SiO2 Coated Li-Rich Li1.2Ni0.13Mn0.54Co0.13O2 Cathode Materials for Li-Ion Batteries

Lithium rich layered oxides (LLO) are one of the potential candidates for Li-ion batteries. however, LLO materials have serious drawbacks such as poor cyclic stability, poor rate capability and rapid voltage decay upon cycling, which needs to be overcome in order to successfully commercialize them. In this work, SiO2 coating is employed (1.0%, 1.5%, and 2.0 wt. %) to combat these issues. Li1.2Ni0.13Mn0.54Co0.13O2 synthesis was carried out by sol-gel process and SiO2 coating was done using dry ball milling method. XRD analysis confirmed the synthesis of phase pure materials without the presence of any impurity phases. SEM and TEM analysis showed the synthesis of nanometric sized particles. Furthermore, TEM elemental mapping displayed the homogeneous distribution of SiO2 on the cathode particles. XPS was further employed to confirm the SiO2 on the cathode material. The electrochemical analysis showed that 1.0 wt.% SiO2 displayed the best performance in terms of rate capability. Uncoated Li1.2Ni0.13Mn0.54Co0.13O2 displayed a fast capacity fade, especially at higher C-rate. On the other hand, SiO2 coated Li1.2Ni0.13Mn0.54Co0.13O2 materials showed improved rate capability. Coated materials also showed improved cycling performance when compared with bare Li1.2Ni0.13Mn0.54Co0.13O2. The improved electrochemical performance can be attributed to the positive impact of SiO2 coating, which impedes the electrolyte oxidation by preventing the direct contact of cathode active material and electrolyte. Overall, the SiO2 coating had a positive impact on the electrochemical performance of Li1.2Ni0.13Mn0.54Co0.13O2 and can pave the way for commercialization of LLO materials.

Continuous supercritical solvothermal preparation of nanostructured ceria-zirconia as supports for dry methane reforming catalysts

The nanostructured CexZr1-xO2 systems (0 ≤ x ≤ 0.75) were prepared combining alkoxide and nitrate precursors in an ethanol/water mixture by the continuous supercritical solvothermal sol-gel like synthesis. They were subsequently used as supports for nickel impregnation (10 wt.%) to obtain catalysts for dry reforming of methane (DRM) reaction. A reference CexZr1-xO2 (x = 0.50) system prepared via conventional coprecipitation method was used as a support for nickel impregnation in the comparative study of the nanostructured materials’ catalytic potential. The morphological and structural properties of the prepared nanostructured supports and Ni-containing catalysts were investigated by numerous techniques as XRD, Raman spectroscopy, SEM, TEM, EDS, chemisorption and others. The conditions of DRM reaction were chosen in order to compare the activity, the stability as well as the selectivity of coke formation in the presence of the prepared catalytic materials. It was found that the industrial catalyst leads to heavy coking in the chosen conditions with a rapid loss of activity. While the nanostructured CexZr1-xO2 (0 ≤ x ≤ 0.75) materials are found to be promising supports for Ni dispersion and coke control in DRM. In this study the nanostructured Ce0.50Zr0.50O2 material impregnated with nickel shown the highest TOF and the smallest selectivity of coke formation in DRM among other nanostructured materials. The continuous supercritical solvothermal method allows to prepare nanostructured mixed oxide materials that could be promising supports for different active metals dispersion and for coke control in the reactions where coking may be abundant.

Epoxy-functionalized silane grafting enhances the cycling performances of Li1.2Ni0.13Co0.13Mn0.54O2 cathode materials

Epoxy-functionalized silane (KH560) modified Li1.2Ni0.13Co0.13Mn0.54O2 materials are prepared by a facile chemical grafting method for the first time. X-ray diffraction confirms that the crystal structure of Li1.2Ni0.13Co0.13Mn0.54O2 is not affected by the KH560 modification. Scanning electron microscopy and transmission electron microscopy results prove that KH560 is homogeneously grafted on the Li1.2Ni0.13Co0.13Mn0.54O2 surface with a thickness of 3–5 nm. The electrochemical tests reveal that the 1.0 wt% KH560 modified Li1.2Ni0.13Co0.13Mn0.54O2 cathodes retain 92.88% (1 C) and 98.24% (5 C) capacity retentions after 100 cycles, respectively, far higher than 83.09% (1 C) and 50.68% (5 C) of the pristine. The improved cycling performances are mainly attributed to the fact that the X-O-M bonds stabilize the surface oxygen and resist the parasitic reactions during cycling, which further can suppress the structure degradation and the impedance increase. This work provides a facile and effective modification method to optimize the interfacial structures of Li1.2Ni0.13Co0.13Mn0.54O2 and/or other cathode materials.

Effect of Al3+ and Al2O3 co-modification on electrochemical characteristics of the 5-V cathode material LiNi0.5Mn1.5O4

Spinel LiNi0.5Mn1.5O4 (LNMO) materials with high voltage and positive cost performance have presented attractive prospects. In this study, an LNMO material was co-modified with Al3+ doping and Al2O3 coating via solid-state method and wet chemical method. The effect of Al3+ doping and different Al2O3 coating which were based on the LNMO samples with a doping content of x = 0.06 on the properties were discussed. Remarkably, the co-modification effect was most favorable when the coating content was 1 wt%; the retention rates after 100 cycles at 0.5C and 2C reached 99.1% and 91.7%, respectively, which can be ascribed to Al3+ doping improving the electronic conductivity of the material. Furthermore, Al2O3 coating can improve ionic conductivity; the LANMO-1 wt% sample got the best charge transfer resistance and Li+ diffusion coefficient. The Al2O3 layer can hinder the side reaction between the material and the electrolyte and reduce the polarization effect, thereby improving the cycle and rate performance of the material.

Li-free P2/O3 biphasic Na0.73Ni0.4Mn0.4Ti0.2O2 as a cathode material for sodium-ion batteries

Mixing P2 and O3 phases in a single material is expected to take advantage of both phases. This work reports the successful synthesis of a Li-free P2/O3 biphasic cathode Na0.73Ni0.4Mn0.4Ti0.2O2 containing 33% of P2 phase by a solid-state method. According to XRD refinement, the interplanar distance along the c-axis decreases from 5.6055 A in the pure P2 material to 5.5710 A in the P2 phase of the biphasic material, while increases from 5.4502 A in the pure O3 material to 5.4855 A in the O3 phase of the biphasic material, indicating different electrostatic repulsions between transitional metal oxide layers. Compared to pure P2 or O3 phase, the biphasic cathode exhibits an initial Coulombic efficiency close to 100%, increased reversible capacity and average voltage, improved cycling stability, and rate performance in the voltage range of 1.5–4.3 V. The biphasic cathode is a promising candidate for full cell application of sodium-ion batteries.

Enhancing surface stability of LiNi0.8Co0.1Mn0.1O2 cathode with hybrid core-shell nanostructure induced by high-valent titanium ions for Li-ion batteries at high cut-off voltage

Achieving a highly stabilized surface structure is the key to successfully enhancing the cycling stability of LiNi0.8Co0.1Mn0.1O2 (NCM) cathode material for Li-ion batteries at high cut-off voltage (4.5 V). In this work, we report a highly surface-stabilized NCM material via a high-valent titanium ion (Ti4+)-induced nanostructured hybrid surface with a core-shell structure. Consequently, the Ti-modified LiNi0.8Co0.1Mn0.1O2 cathode provides an excellent cycling stability with 92.3% capacity retention (100 cycles, 0.5C, 2.7–4.5 V). This proposed hybrid core-shell nanostructure prominently mitigates the surface structural degradations, continuous microcracking and parasitic reactions, effectively improving the surface structural stability. This efficient strategy provides a step towards further commercial application of the LiNi0.8Co0.1Mn0.1O2 material and can be extended to other layered cathode materials.

Electrochemical performance of Sn-doped cobalt-free Li1.15Ni0.27Mn0.58-xSnxO2 cathode material for Li-ion batteries

In this study, a series of cobalt-free Sn-doped cathode materials of Li1.15Ni0.27Mn0.58-xSnxO2 are prepared by the solvothermal method for the first time. The structural characterization of the material reveals that all the samples consist of hexagonal layered structural LiMO2 (M = Mn/Ni), monoclinic-layered structural Li2MnO3, and cubic spinel structural LiMn2O4. Moreover, the interplanar spacing of the layered structure increases in the material, and the electrochemical impedance of the material declines by Sn doping. As a result, all Sn-doped samples exhibit better electrochemical performance than pristine Li1.15Ni0.27Mn0.58O2 materials. Among them, Li1.15Ni0.27Mn0.56Sn0.02O2 delivers comprehensively improved electrochemical performance. The initial coulombic efficiency of the Li1.15Ni0.27Mn0.56Sn0.02O2 sample is 84.4%, which is nearly 10% higher than the pristine material, and Li1.15Ni0.27Mn0.56Sn0.02O2 exhibits an initial discharge specific capacity of 260.8 mAh/g at a current density of 0.1 C, and the capacity retention after first 100 cycles at 1 C reached 94.67%. Rate capability of Li1.15Ni0.27Mn0.58-xSnxO2 is significantly improved by Sn doping. The specific discharge capacity of the Li1.15Ni0.27Mn0.56Sn0.02O2 sample at 5 C is two times higher than that of Li1.15Ni0.27Mn0.58O2. Moreover, the Li1.15Ni0.27Mn0.56Sn0.02O2 material can still maintain a discharge capacity of 220 mAh/g when the current density returns to 0.1 C after a large current density cycling process. These results show that the proper amount of Sn doping can effectively improve the electrochemical performance of Li1.15Ni0.27Mn0.58O2, due to the fact that Sn ions have larger ionic radii than the transition metal (Mn/Ni) ions and Sn can partially replace the transition metal element ions in the layered structure, thereby expanding the lithium ion diffusion channel and inhibiting instability of the material structure during the cycle. However, an excessive amount of Sn (x > 0.03) generates a Li2SnO3 impurity in the material, resulting in deterioration of material properties.

Effects of gradient concentration on the microstructure and electrochemical performance of LiNi0.6Co0.2Mn0.2O2 cathode materials

Nickel(Ni)-rich layered materials have attracted considerable interests as promising cathode materials for lithium ion batteries (LIBs) owing to their higher capacities and lower cost. Nevertheless, Mn-rich cathode materials usually suffer from poor cyclability caused by the unavoidable side-reactions between Ni4+ ions on the surface and electrolytes. The design of gradient concentration (GC) particles with Ni-rich inside and Mn-rich outside is proved to be an efficient way to address the issue. Herein, a series of LiNi0.6Co0.2Mn0.2O2 (LNCM622) materials with different GCs (the atomic ratio of Ni/Mn decreasing from the core to the outer layer) have been successfully synthesized via rationally designed co-precipitation process. Experimental results demonstrate that the GC of LNCM622 materials plays an important role in their microstructure and electrochemical properties. The as-prepared GC3.5 cathode material with optimal GC can provide a shorter pathway for lithium-ion diffusion and stabilize the near-surface region, and finally achieve excellent electrochemical performances, delivering a discharge capacity over 176 mAh·g−1 at 0.2 C rate and exhibiting capacity retention up to 94% after 100 cycles at 1 C. The rationally-designed co-precipitation process for fabricating the Ni-rich layered cathode materials with gradient composition lays a solid foundation for the preparation of high-performance cathode materials for LIBs.

Enhancement of ferroelectric and ferromagnetic properties of Gadolinium (Gd) and Nickel (Ni) co-doped BiFeO3

The structural, vibrational, optical, ferroelectric, and ferromagnetic properties of single phase BiFeO3 (BFO) and Bi1-xGdxFe0.975Ni0.025O3 (x ~ 0.00, 0.025, 0.05, 0.075, 0.10, 0.125, and 0.15) materials, synthesized by sol-gel method have been investigated systematically using different techniques. X-ray diffraction patterns (XRD) revealed that all samples crystallized in single phase and showed a compressive lattice distortion with increasing Gd-doping concentration. A structural phase transition from rhombohedral to orthorhombic took place at co-doped sample with x = 0.125 which was evidenced by both XRD analyses and Raman scattering spectra. Optical band gap was slightly decreased with Gd-doping content. Ni and Gd co-substitution in BFO caused a remarkable enhancement of both ferroelectric and ferromagnetic properties which was demonstrated by the sharp increasing of maximum (Ps) and remnant (Pr) polarization, dielectric constant (ε), saturation (Ms) and remnant (Mr) magnetization. Our results indicated the effective contributions of Ni-doping and Gd-doping in the innovations of ferromagnetism and ferroelectricity of BFO, respectively.

Li2TiO3 and Li2ZrO3 co-modification LiNi0.8Co0.1Mn0.1O2 cathode material with improved high-voltage cycling performance for lithium-ion batteries

LiNi0.8Co0.1Mn0.1O2 (NCM) materials with surface modification by Li2TiO3 (LTO), Li2ZrO3 (LZO) and Li2TiO3-Li2ZrO3 (LTZO) coatings are successfully synthesized via a simple wet chemical method and proper heat-treatment process. The crystal structure, surface morphology, valence states and electrochemical properties of different modified NCM materials are investigated by the means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The NCM co-modified by Li2TiO3 and Li2ZrO3 composite coatings (LTZO@NCM) shows remarkable improvements in cycling performance and rate capability, the discharge capacity is 190.36 mAh g−1 with high capacity retention of 92.64% at 0.2C after 100 cycles between 2.75 and 4.4 V, compared to 174.83 mAh g−1 with the capacity retention of 87.20% for pristine NCM. Even at a high current density of 1 C, LTZO@NCM still maintains a high discharge capacity of 149.77 mAh g−1 cycled at high cut-off voltage of 4.4 V, with a capacity retention rate of 83.04% at 150th cycle, while bare NCM only delivers 123.92 mAh g−1 with capacity retention of 68.86%. The enhanced electrochemical performance can be ascribed to the modified effect of LTZO nano-coating layer on the NCM surface. LTZO nano-coating layer can not only effectively protect NCM particles, avoid the occurrence of side reaction, but also provide a better Li+ transport channels, improve lithium ion diffusion rate and enhance the structure stability and electrochemical performances of NCM material.

Microwave reduction enhanced leaching of valuable metals from spent lithium-ion batteries

Abstract The growing demand for high-energy lithium-ion batteries (LIBs) has promoted the production of LiNixCoyMnZO2 cathode, which results in many spent LIBs to resolve. A novel method that employs microwave carbothermic reduction was used to enhance the leaching of metals from layered LiNi1/3Co1/3Mn1/3O2 of spent LIBs. The thermodynamic analysis showed that LiNi1/3Co1/3Mn1/3O2 could be theoretically reduced to single metals in the presence of graphite. Then experimental results demonstrated that the transition metals can be effectively reduced under the parameters of 500 W microwave energy and 30min time. Afterward, multiscale characterizations revealed that microwave irradiation leads to the disorderly crystal structure and lattice cracks of LiNi1/3Co1/3Mn1/3O2 materials, which is more efficient to facilitate their interparticle liberation and destruction of crystal structure compared with the conventional heating process. Based on the characterization of the reduction products and their leaching performance, the mechanism for microwave carbothermic reduction was accordingly raised. Finally, the leaching experimental results show the optimal efficiencies of 97% transition metals (Co Ni, and Mn) and 99% Li were obtained under microwave carbothermic reduction, which is found more efficient in comparison to the samples without microwave treated. The whole process is found to be effective and sustainable for recovery of valuable metals from the industrial electrode of spent LIBs.

Highly-ordered microstructure and well performance of LiNi0.6Mn0.2Co0.2O2 cathode material via the continuous microfluidic synthesis

Ni-rich layered oxides are potential cathode candidate’s materials for Li-ion batteries due to their low cost and high energy density. However, it is difficult to reproducibly prepare uniformly distributed element and well-controlled morphology of Ni-rich layered oxide particles. This study develops a continuous microfluidic reaction process to synthesize spherical carbonate precursors (Ni0.6Mn0.2Co0.2CO3). The as-synthesized LiNi0.6Co0.2Mn0.2O2 materials exhibit well-defined microsphere morphology, uniform particles size distribution, better thermal stability and homogeneous transition metal distribution, due to the excellent mixing, well mass and heat transfer rate during the microfluidic reaction. Moreover, the as-prepared LiNi0.6Co0.2Mn0.2O2 materials achieve higher initial capacity, excellent electrochemical reversibility and capacity retention than that of the samples prepared by traditional co-precipitation. Therefore, our results demonstrate that microfluidic reaction is a simple and effective synthesis technology for preparing Ni-rich layered cathode.