Synthesis Of LiNi0 Research Articles

Synthesis of LiNi0.9Co0.05Mn0.05O2 and modification with co-doping of Zr4+ and W6+ using acid leaching solution from spent lithium-ion batteries

Synthesis of LiNi0.9Co0.05Mn0.05O2 and modification with co-doping of Zr4+ and W6+ using acid leaching solution from spent lithium-ion batteries

Synthesis of LiNi0.8Co0.1Mn0.1O2 cathode material with high energy density using di-butylamine as precipitant

Synthesis of LiNi0.8Co0.1Mn0.1O2 cathode material with high energy density using di-butylamine as precipitant

Enhanced cycle performance and synthesis of LiNi0.6Co0.2Mn0.2O2 single-crystal through the assist of Bi ion

LiNi0.6Co0.2Mn0.2O2 (NCM622) single-crystal material was successfully prepared by introducing Bi ions. The influence of Bi ions introduction on the morphology, structure, and performance of NCM622 single-crystal material was explored. Introducing Bi ions can promote the growth of the primary particles of the cathode, and the NCM622 single-crystal material can be synthesized at a lower temperature. The single-crystal synthesized with the help of Bi ions can improve the interfacial stability of the material surface. And at a rate of 1C and voltage range of 2.8–4.3 V, the sample with 4000 ppm Bi addition introduced has a cycle retention rate of 88.67 % after 150 cycles. Simultaneously, we used SEM, XRD, EDS, TEM, XPS, and EBSD to reveal how Bi ions promote the generation of single-crystal morphology of cathode.

Unraveling the Correlation between the Synthesis Time and Electrochemical Performance of Transition Metal Layered Oxides by In Situ Neutron Powder Diffraction

Ni-rich layered transition metal oxides are promising cathodes for Li-ion batteries due to their low cost and high theoretical capacity. However, their practical applications are hindered by the capacity fading caused by intrinsic lattice structure variations, such as changes in the atom arrangement and valence. In situ neutron powder diffraction is a powerful technique for studying the structure of battery materials and is expected to provide more information than other techniques due to its nondestructive, high-resolution, and light-element probing capability. Herein, we employed neutron powder diffraction to probe the structural evolution during the synthesis of LiNi0.5Co0.2Mn0.3O2 in real time, including the transition metal–oxygen/lithium–oxygen (TM–O/Li–O) bond, phase formation, and lattice parameters as a function of temperature and isothermal dwelling time. The results revealed that the lattice structure of cathode materials is a function of temperature and isothermal dwelling time. Variations of the TM–O/Li–O bond and lattice parameters with the dwelling time at an annealing temperature of 850 °C indicated that the instability of the structure of the layered transition metal oxides may be a possible mechanism for the changes in the discharging capacity and cycle stability of the battery performance. Our findings provide insights into the correlation between the annealing time of NCM cathodes and the electrochemical performance and can be very helpful for synthesizing high-performance transition metal layered oxide materials.

Real-time X-ray analytical micro-furnace technique for in situ phase formation analysis during material synthesis

The monitoring of real-time reaction mechanisms can provide authentic structural information related to the prepared materials. This study reports the development of a novel real-time X-ray analytical micro-furnace (RT-XAMF) technique, which is applied during the synthesis of LiNi0.8Co0.15Al0.05O2 to monitor the phases present between 30 and 850 °C. To ensure stable temperature control during heating and ensure the practicality of the RT-XAMF technology, an insulating block was developed that allowed a small temperature tolerance of ±0.5 °C up to 1000 °C. Detailed information was gathered regarding the optimal heat treatment conditions for layered structure formation, and in the Li-excess LiNi0.8Co0.15Al0.05O2 electrode material, high charge and discharge capacities were obtained. The formation of a layered structure was monitored upon mixing various lithium salts (LiOH·H2O, Li2CO3, LiNO3, and LiF) with the Ni0.8Co0.15Al0.05(OH)2 precursor. Our results indicate that this RT-XAMF technology can be applied in the development of metal oxides and ceramic materials.

Enhanced cycle performance and synthesis of LiNi0.6Co0.2Mn0.2O2 single-crystal through the assist of Ba ion

The single-crystal materials of Ni-based layered oxides have drawn in wide consideration due to excellent cycle performance and storage performance. However, the conditions for synthesizing Ni-based layered oxides with a single-crystal morphology are extremely demanding. In this research, Ba2+ is introduced into the synthesis process of LiNi0.6Co0.2Mn0.2O2 single-crystal material (SC-NCM) to assist the formation of single-crystal materials. Furthermore, this work proposes an inference that the introduction of Ba2+ reduces the diffusion energy at the grain boundaries of the cathode particles, promoting particle coalescence. The role of Ba2+ in this system is investigated using X-ray diffraction, scanning electron microscope, energy-dispersive x-ray spectroscopy, transmission electron microscopy, thermogravimetric analysis and differential thermal analysis. As a consequence, introducing Ba2+ promotes the formation of single crystal morphology and improves the cycle performance of the cathode.

Green and efficient synthesis of LiNi0.8Co0.1Mn0.1O2 cathode material with outstanding electrochemical performance by spray drying method

Green and efficient synthesis of LiNi0.8Co0.1Mn0.1O2 cathode material with outstanding electrochemical performance by spray drying method

LiNi0.8Co0.15Ti0.05O2: synthesis by solid state reaction and investigation of structural and electrochemical properties with enhanced battery performance

Solid state synthesis is an essential technique for large-scale production of electrode active materials in battery industry. However, solid state synthesis of LiNi0.8Co0.15Al0.05O2 (NCA), which is a well-known commercial cathode material for Li-ion batteries, provides electrochemically inactive compound. Here, we report the solid state synthesis of LixNi0.8Co0.15Ti0.05O2 where x = 1.03, 1.06, and 1.09, which is a modified version of conventional NCA. Our thorough studies consist of characterization of compounds by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and magnetization measurements. The results point out the significant effects of Li content on structural and magnetic properties of the samples. Battery performance tests show that Li1.06Ni0.8Co0.15Ti0.05O2 exhibits better cycling properties than conventional NCA. X-ray absorption spectroscopy (XAS) technique is utilized to determine structural modifications upon cycling of this compound via ex-situ analysis. We conclude that substitution of Ti ions in Li1.06Ni0.8Co0.15Ti0.05O2 improves the cycling capability of the cells by reducing the formation of NiO insulating layer which hinders the redox reactions. The capacity value of x = 1.06 sample increases up to 150 mAh g−1 at C/3 rate during cycling and the capacity fade is negative for the first 10 cycles. Possible mechanism for the negative capacity fade is also discussed.

Flux synthesis of LiNi0.5Co0.2Mn0.3O2 via in situ self-oxygenation

A new flux synthesis is elaborately designed to synthesize LiNi0.5Co0.2Mn0.3O2 whose precursor is prepared by room-temperature solid-state reactions with the simultaneous formation of a composite flux medium NaNO3-NaCl. The NaNO3 in the precursor can release oxygen via thermal decomposition and thus an inner oxygen-rich environment within molten salt can be in situ created and ensures sufficient oxidation of partial Ni2+ to Ni3+ during flux synthesis of LiNi0.5Co0.2Mn0.3O2. Our comparative experiments demonstrate that this in situ self-oxygenation can then reduce the Li+/Ni2+ mixing in the obtained LiNi0.5Co0.2Mn0.3O2 and ultimately improved electrochemical performance is achieved as compared with that obtained by the traditional flux synthesis.

Synthesis of LiNi0.8Co0.15Al0.05O2 cathode material via flame-assisted spray pyrolysis method

Long reaction and long heat treatments have become major obstacles in producing cathode materials NCA (LiNi0.8Co0.15Al0.05O2) for Li-ion batteries. Flame assisted spray pyrolysis (FASP) method followed by sintering process requires shorter reaction and sintering time and considered suitable economical alternative in NCA production. The obtained ternary oxides particles from FASP have high crystalline and homogenous properties. Furthermore, XRD pattern of NCA products obtained by lithiation of ternary oxides exhibit well-ordered layered hexagonal structure. Electrochemical performance of NCA was tested in an NCA/graphite system at 2.7–4.3 V and current density of 20 mA/g. At the optimum sintering condition (under O2 rich atmosphere for 9 h), NCA particles show the initial specific discharge capacity of 143 mAh/g, and the capacity retention of 92% after 20 cycles. This results is higher from commercial available NCA particles (specific discharge capacity of 138 mAh/g) which indicates the promise of this approach for NCA production.

Thermal plasma synthesis and electrochemical properties of high-voltage LiNi0.5Mn1.5O4 nanoparticles

The synthesis of LiNi0.5Mn1.5O4 has been reported to change the crystal structure with the oxygen partial pressure and affect the battery characteristics. LiNi0.5Mn1.5O4 involves the formation of impurities, such as LixNi1−xO, LixMn3−xO4, and Li2CO3, at a high temperature range exceeding 700 °C because oxygen loss occurs during synthesis. LiNi0.5Mn1.5O4 electrochemically contains Mn4+, however, Mn3+ is formed because of oxygen deficiency. The Li–Ni–Mn-oxide causes a disproportionation of Mn3+ in an oxygen-deficient state. The synthesized Li–Ni–Mn-oxide nanoparticles at 10,000 K by induction thermal plasma formed spinel-type LiNi0.5Mn1.5O4 (space group Fd3m) of Mn4+. The crystal structure of the cubic-spinel nanoparticles approached a LiNi0.5Mn1.5O4 single phase as the flow rate of O2 increased from 2.5 to 5 l min−1. The formation of LiNi0.5Mn1.5O4 was shown to be accelerated by increasing the O2 gas flow rate. The measured current–voltage characteristics of LiNi0.5Mn1.5O4 nanoparticles appeared at around 4.7–4.8 V as the reaction peak of Ni2+/Ni3+ and Ni3+/Ni4+. In contrast, the Mn of the Li–Ni–Mn-oxide nanoparticles synthesized in the oxygen-deficient state was less than trivalent, which caused disproportionation of Mn. The measured current-voltage characteristics showed peak of an oxygen desorption at near 4.6 V. This study investigated the factors affecting the crystal structure formation and electrochemical properties of high-voltage LiNi0.5Mn1.5O4 nanoparticles formed in thermal plasma.

Synthesis of LiNi0.6Co0.2Mn0.2O2 from mixed cathode materials of spent lithium-ion batteries

With the aggravation of resource shortage and environmental problems, the disposal of spent lithium-ion batteries becomes crucial. In this work, a sustainable closed-loop route to recycle mixed cathode materials from spent lithium-ion batteries is proposed. The sulfuric acid and H2O2 were used to leach mixed cathode powders, and parameters such as temperature, acid concentration, and time were investigated. The leaching efficiency of each metal was observed to be above 99%. The ternary cathode precursor was directly prepared from leachate. Li2CO3 was recovered from the residual solution by adding saturated Na2CO3. The mixture of precursor and Li2CO3 was roasted to resynthesize ternary cathode materials (LiNi0.6Co0.2Mn0.2O2). The characterization of LiNi0.6Co0.2Mn0.2O2, as well as its electrochemical performance was investigated. LiNi0.6Co0.2Mn0.2O2 possesses a layered structure and shows excellent cycling stability and rate capacity. The capacities at the first charge and discharge at 0.2C are 196.26 mA h·g−1 and 180.072 mA h·g−1, respectively. The coulombic efficiency after the second cycle is observed to be about 99%.

Thermodynamic analysis of Li-Ni-Co-Mn-H2O system and synthesis of LiNi0.5Co0.2Mn0.3O2 composite oxide via aqueous process

The constructed potential-pH diagrams of Li-Ni (Co, Mn)-H2O system indicate that the LiNiO2, LiCoO2 and LiMnO2 are thermodynamically stable in aqueous solution within the temperature range of 25-200 °C and the activity range of 0.01-1.00. A predominant co-region of LiNiO2, LiCoO2 and LiMnO2 oxides (Li-Ni-Co-Mncomposite oxide) is found in the Li-Ni-Co-Mn-H2O potential-pH diagrams, in which the co-precipitation region expands towards lower pH with rising temperature, indicating the enhanced possibility of synthesizing Li-Ni-Co-Mn composite oxide in aqueous solution. The experimental results prove that it is feasible to prepare the LiNi0.5Co0.2Mn0.3O2 cathode materials (NCM523) by an aqueous routine. The as-prepared lithiated precursor and NCM523 both inherit the spherical morphology of the hydroxide precursor and the obtained NCM523 has a hexagonal α-NaFeO2 structure with good crystallinity. It is reasonable to conclude that the aqueous routine for preparing Ncm cathode materials is a promising method with the guidance of the reliable potential-pH diagrams to some extent.

Synthesis of LiNi0.85Co0.14Al0.01O2 Cathode Material and its Performance in an NCA/Graphite Full-Battery

Nickel-rich cathode material, NCA (85:14:1), is successfully synthesized using two different, simple and economical batch methods, i.e., hydroxide co-precipitation (NCA-CP) and the hydroxides solid state reaction method (NCA-SS), followed by heat treatments. Based on the FTIR spectra, all precursor samples exhibit two functional groups of hydroxide and carbonate. The XRD patterns of NCA-CP and NCA-SS show a hexagonal layered structure (space group: R_3m), with no impurities detected. Based on the SEM images, the micro-sized particles exhibit a sphere-like shape with aggregates. The electrochemical performances of the samples were tested in a 18650-type full-cell battery using artificial graphite as the counter anode at the voltage range of 2.7–4.25 V. All samples have similar characteristics and electrochemical performances that are comparable to the commercial NCA battery, despite going through different synthesis routes. In conclusion, the overall results are considered good and have the potential to be adapted for commercialization.

Synthesis of LiNi0.8Mn0.1Co0.1O2 by an Oxalate Precipitation

Batteries with high energy densities and long cycle lives are important for enabling the transition from fossil fuels to electrical vehicles. Lithium ion batteries are the most popular batteries for use in electrical vehicles, but there is still a need to increase the gravimetric and volumetric energy densities from state-of-the-art batteries without increasing the costs. Since cobalt is one of the most costly and also toxic elements used in the cathode, developing low cobalt chemistries is highly desirable. LiNixMnyCozO2 (x+y+z = 1; NMC) with high Ni content is one of the cathode materials which has received attention because its high capacity and energy density. The capacity of NMC increases with increasing Ni content because Ni is the main electrochemically active transition metal in NMC. However, the capacity retention and thermal stability decreases with increasing Ni content as well [1]. Still, there is research on stabilising NMC with high Ni content, such as LiNi0.8Mn0.1Co0.1O2 (NMC 811), both with respect to performance and safety. An example of such an effort is to coat NMC 811 with AlPO4 [2]. NMC has a layered structure with lithium ions and transition metal ions in separate layers. One of several reasons for the capacity fade of NMC during cycling is cation mixing, where some Ni2+ and Li+ switch positions in the structure because of their similar ionic radii, blocking pathways for Li+ during lithiation and delithiation [3, 4, 5]. Work performed by Huaquan Lu et al. (2013) on NMC 811 indicates that the synthesis method may affect both morphology and degree of cation mixing [6]. In this work, the effect of different experimental parameters on quality of the synthesised material is studied. NMC 811 was synthesised by an oxalate precipitation from transition metal acetates and lithium nitrate precursors, adapted from a method described by Zhen Chen et al. [7]. Initial results show a phase pure layered structure with low cation mixing. Further work will include adjusting different experimental parameters, such as precursor mixing sequences, precursor mixing rates, annealing temperatures and atmosphere, in an effort to optimise the synthesis. The success of the synthesis will be evaluated based on factors such as phase purity, cation mixing, and electrochemical performance.

Synthesis of LiNi0.8Mn0.1Co0.1O2 cathode material by hydrothermal method for high energy density lithium ion battery

The synthesis of LiNi0.8Mn0.1Co0.1O2 (LNMC) material had been performed via hydrothermal method. LNMC materials as Li-ion battery cathode is chosen because it has many advantages, such as the availability of abundant materials, low cost, high capacity and superior performance of the battery. In this research, hydrothermal method is chosen because it can increase the size of crystallite with good structure hence the crystal quality is improved which is advantageous to improve battery capacity and cycle performance. The novelty of this study is the use of nickel sulfate, manganese sulfate and cobalt sulfate as the transitional metal source of LNMC. The hydrothermal temperature was varied between 160°C - 190°C. Based on X-ray Diffraction test (XRD), LNMC material has crystallite size in the range 45.37 - 46.74 nm. While based on the chargedischarge test, the resulting LNMC cathode battery has a capacity value in the range 0.0453 - 1.199 mAh/g. The highest capacity was obtained on batteries using LNMC cathode electrodes synthesized at 190° C hydrothermal (LNMC H-190 samples). This could be caused by large crystallite size of the sample. As the size of the crystal increases, the Li+ ion intercalation pathways will be wider hence the storage capacity is also greater.

Flame Aerosol Synthesis and Electrochemical Characterization of Ni-Rich Layered Cathode Materials for Li-Ion Batteries

We report on the synthesis of LiNi0.8Co0.1Mn0.1O2 (NCM811) Li-ion battery cathode materials using an aerosol of micron-size aqueous metal nitrate solution droplets delivered to non-premixed flames....

Synthetic Control and Structural Stabilization of Ni-Rich Layered Oxides As High-Energy Cathode Materials for Lithium Ion Batteries

Ni-rich layered oxides (LiNi1-xMxO2, M=Co, Mn, Al, etc., x<0.5) have been demonstrated as practical cathode materials for high-energy and high-power lithium ion batteries. However, various synthetic factors affect the layered structural ordering of LiNi1-xMxO2 and related electrochemical lithium storage performances. Herein, we report on developing a high-capacity Ni-rich LiNi0.8Co0.1Mn0.1O2 oxide with enhanced cycleability via the synthetic control. Systemic investigation is made to the phase evolution of LiNi0.8Co0.1Mn0.1O2 oxide under different annealing temperatures by ex-situ and in-situ synchrotron X-ray diffraction (XRD) measurements, coupled with quantitative structural analysis through refinements. Structural characterization indicates an intriguing phase transition of LiNi0.8Co0.1Mn0.1O2 from a rock-salt structure at low annealing temperatures directly to a layered α-NaFeO2-type structure with a R-3m space group at high temperatures. The in-situ XRD studies gain us access to the phase diagram in the confined Ni-rich region of the Ni-Mn-Co space, thereby enabling the design of synthetic protocols for preparing high-capacity LiNi1-x-yMnxCoyO2 oxides with stabilized structure and reasonable cycling stability. Furthermore, a preheating process and Li2TiO3 coating layer have been introduced during the synthesis of LiNi0.8Co0.1Mn0.1O2 oxide, in order to manipulate the lithium source reaction by fabricating the outer shell in advance. As a result, the resulting LiNi0.8Co0.1Mn0.1O2 cathode material reveals the higher degree of structural ordering and considerably enhanced lithium storage performances. This work offers a feasible route to optimize the layered structure of Ni-rich cathode materials via the synthetic control of the lithium source reaction, and further sheds light on the fundamental relationship between crystal structure and electrochemical performance for high-energy lithium ion batteries.

Synthesis and characterization of LNMO cathode materials for lithium-ion batteries

Synthesis of LiNi0.5Mn1.5O4 (LNMO), a promising cathode material for next generation lithium-ion batteries, was performed via Liquid Phase Self-propagating High-temperature Synthesis (LPSHS) and Aerosol Spray Pyrolysis (ASP) techniques. In the case of the LPSHS technique, the effect of the “fuel” quantity of the precursor solution on the structure, morphology and electrochemical performance of the materials was studied, while in the case of the ASP technique the effect of eight different calcination profiles on the structure, morphology, crystalline phase and electrochemical performance of the material. Structural characterization was performed through XRD, SEM, TEM, BET and Raman spectroscopy, while the electrochemical activity was evaluated via charge/discharge galvanostatic characterization. The results showed that the optimal LPSHS material was obtained for a molar ratio of metal ions/fuel = 3:1 exhibiting stable specific capacity over the cycles even by increasing the C-rate. Τhe optimal ASP material was identified in the case of calcination at 850°C. Both materials had the disordered Fd-3m structure of the LNMO spinel

Synthesis of LiNi0.5Mn1.5O4 nano/microspheres with adjustable hollow structures for lithium-ion battery

High-voltage spinel LiNi0.5Mn1.5O4 nano/microspheres with adjustable hollow structures have been fabricated based on the Kirkendall effect. The main characteristic is that the wall thickness of the hollow structure as well as the cavity size of the hollow structure can be adjusted by the different ratio of mixed precipitation agents. Especially, the diagrammatic sketch for the formation process of various LiNi0.5Mn1.5O4 materials with adjustable hollow structures is discussed. Besides, the results of electrochemical performance test show that LiNi0.5Mn1.5O4 obtained from 10:1 Na2CO3/NaOH (in mole) ratio is worth looking forward to, owing to its special hierarchical nano/microsphere and moderate hollow structures.