One-Spot Facile Synthesis of Single-Crystal LiNi0.5Co0.2Mn0.3O2 Cathode Materials for Li-ion Batteries (original) (raw)
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Properties of LiNi 0.8 Co 0.1 Mn 0.1 O 2 as a high energy cathode material for lithium-ion batteries
−Nickel-rich layered materials are prospective cathode materials for use in lithium-ion batteries due to their higher capacity and lower cost relative to LiCoO 2. In this work, spherical Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 precursors are successfully synthesized through a co-precipitation method. The synthetic conditions of the precursors-including the pH, stirring speed, molar ratio of NH 4 OH to transition metals and reaction temperature-are investigated in detail, and their variations have significant effects on the morphology, microstructure and tap-density of the prepared Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 precursors. LiNi 0.8 Co 0.1 Mn 0.1 O 2 is then prepared from these precursors through a reaction with 5% excess LiOH· H 2 O at various temperatures. The crystal structure, morphology and electrochemical properties of the Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 precursors and LiNi 0.8 Co 0.1 Mn 0.1 O 2 were investigated. In the voltage range from 3.0 to 4.3 V, LiNi 0.8 Co 0.1 Mn 0.1 O 2 exhibits an initial discharge capacity of 193.0 mAh g −1 at a 0.1 Crate. The cathode delivers an initial capacity of 170.4 mAh g −1 at a 1 Crate , and it retains 90.4% of its capacity after 100 cycles.
Journal of Power Sources, 2018
Some scientific studies report that the use of nanosized cathode materials can improve the electrochemical performances of a battery. In fact, these materials can open new and important perspectives for cathode materials such as their use for power applications or for technologies for which an optimized interface with the electrolyte is required (e.g all solid state battery or polymer battery). However, the high scale production and the processing of these powders to obtain dense electrodes are difficult. In this study, submicronic particles of LiNi 1/ 3 Mn 1/3 Co 1/3 O 2 are synthesized using an easy and scalable coprecipitation synthesis protocol. Isolated particles of 200 nm are obtained and are fully characterized. The non-agglomerated morphology of this material improves the accessibility of the lithium insertion planes, and consequently, the high Crate behavior is clearly improved as compared to classic agglomerate materials. The difficult processing of submicronic particles is overcome thanks to an environmentally-friendly water-based formulation. Proof-of-concept Li-ion cells have been realized. Although submicronic particles are used, the cell is manufactured with a cathode loading of 18.8 mg cm −2 which is relevant for commercial application.
Electrochimica Acta, 2009
LiNi 1/2 Mn 1/2 O 2 electrodes with layered structure were synthesized by solid-state reaction between lithium hydroxide and mixed Ni,Mn oxides obtained from co-precipitated Ni,Mn carbonates and hydroxides and freeze-dried Ni,Mn citrates. The temperature of the solid-state reaction was varied between 800 and 950 • C. This method of synthesis allows obtaining oxides characterized with well-crystallized nanometric primary particles bounded in micrometric aggregates. The extent of particle agglomeration is lower for oxides obtained from freeze-dried Ni,Mn citrates. The local Mn 4+ surrounding in the transition metal layers was determined by X-band electron paramagnetic resonance (EPR) spectroscopy. It has been found that local cationic distribution is consistent with ␣,-type cationic order with some extent of disordering that depends mainly on the precursors used. The electrochemical extraction and insertion of lithium was tested in lithium cells using Step Potential Electrochemical Spectroscopy. The electrochemical performance of LiNi 1/2 Mn 1/2 O 2 oxides depends on the precursors used, the synthesis temperature and the potential range. The best electrochemical response was established for LiNi 1/2 Mn 1/2 O 2 prepared from the carbonate precursor at 900 • C. The changes in local environment of Mn 4+ ions during electrochemical reaction in both limited and extended potential ranges were discussed on the basis of ex situ EPR experiments.
Australian Journal of Chemistry, 2013
Nickel-doped lithium manganate spinels are a potential material for future energy storage owing to high cell potential and low price. Phase-pure spinels are difficult to prepare by conventional solid-state synthesis methods owing to loss of oxygen from the crystal lattice at high temperature (,8008C). Loss of oxygen causes Jahn-Teller distortion and Mn 4þ is converted into Mn 3þ , which results in undesired double-plateau discharge and reduction in capacity and stability of the material. In this study, nanocrystalline phase-pure LiNi 0.5 Mn 1.5 O 4 was prepared by co-precipitation with cyclohexylamine followed by calcination at a low temperature of 5008C. X-ray diffraction studies confirmed that a highly crystalline face-centred cubic product is formed with F-d3m space group. Scanning electron microscopy and transmission electron microscope studies confirmed that the particles are in the nano range with a porous structure. The as-prepared LiNi 0.5 Mn 1.5 O 4 showed a high initial specific capacity (up to 130 mA h g À1 ) and retained up to 120 mA h g À1 up to 50 cycles. The material has high conductivity and remains stable up to a 20-C discharge rate.
International Journal of Molecular Sciences
Elemental doping for substituting lithium or oxygen sites has become a simple and effective technique to improve the electrochemical performance of layered cathode materials. Compared with single-element doping, this work presents an unprecedented contribution to the study of the effect of Na+/F− co-doping on the structure and electrochemical performance of LiNi1/3Mn1/3Co1/3O2. The co-doped Li1-zNazNi1/3Mn1/3Co1/3O2-zFz (z = 0.025) and pristine LiNi1/3Co1/3Mn1/3O2 materials were synthesized via the sol–gel method using EDTA as a chelating agent. Structural analyses, carried out by X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy, revealed that the Na+ and F− dopants were successfully incorporated into the Li and O sites, respectively. The co-doping resulted in larger Li-slab spacing, a lower degree of cation mixing, and the stabilization of the surface structure, which substantially enhanced the cycling stability and rate capability of the cathode material...
ACS Energy Letters, 2019
Ni-rich materials of layered structure LiNi x Co y Mn z O 2, x > 0.5 are promising candidates as cathodes in high energy density Li-ion batteries for electric vehicles. The structural and cycling stability of Ni-rich cathodes can be remarkably improved by doping with small amount of extrinsic multivalent cations. In this study, we examine development of fast screening methodology for doping LiNi 0.8 Co 0.1 Mn 0.1 O 2 with cations Mg 2+ , Al 3+ , Si 4+ , Ti 4+ , Zr 4+ and Ta 5+ by a "top down" approach. The cathode material is coated by a precursor layer that contains the dopant, which then is introduced into the particles by diffusion during heat treatment at elevated temperatures. The methodology described herein can be applied to Ni-rich cathode materials and allows to identify relatively easily and promptly most promising dopants. Then further optimization work can lead to development of high capacity stable cathode materials. The present study marks Ta 5+ cations as very promising dopants for Ni-rich NCM cathodes.
Journal of Power Sources, 2019
The targeted optimization of Li-ion batteries (LIBs) requires a fundamental understanding of the wide variety of interdependencies between electrode design and electrochemical performance. In the present study, the effects of thickness and porosity on the electrochemical performance and Li-ion insertion kinetics of LiNi 0.6 Co 0.2 Mn 0.2 O 2-based (NCM-622) cathodes are investigated. Cathodes of different thickness and porosity are prepared and analyzed regarding their rate capability. The polarization behavior is investigated using electrochemical impedance spectroscopy. A simple mathematical model is employed to estimate the impact of Li-ion diffusion limitations in the electrolyte. The results are considered at both, the materials and the full-cell level. The design parameters are found to have distinct impact on the electrolyte, contact and charge transfer resistance as well as the Li-ion diffusion limitations in the electrolyte, significantly influencing the rate capability. The results attest an inherent tradeoff between energy and power density. The insights of this study can be used straightforward for the optimization of gravimetric and volumetric energy density of LIBs depending on the desired application.
ChemElectroChem, 2015
An integrated layered-spinel LiNi 0.33 Mn 0.54 Co 0.13 O 2 was synthesized by self-combustion reaction (SCR), characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. It was studied as a cathode material for Li-ion batteries and its electrochemical performance was compared with that of the layered cathode materialLiNi 0.33 Mn 0.33 Co 0.33 O 2 being operated at a wide potential window. The Rietveld analysis of LiNi 0.33 Mn 0.54 Co 0.13 O 2 indicated the presence of monoclinic Li[Li 1/3 Mn 2/3 ]O 2 (31%) and rhombohedral (LiNi x Mn y Co z O 2 ) (62 %) phases as the major components, and spinel (LiNi 0.5 Mn 1.5 O 4 ) (7 %) as a minor component, which is well supported by TEM and electron diffraction. A discharge specific capacity of about 170 mAh g -1 is obtained in the potential range of 2.3-4.9 V vs. Li at low rate (C/10) with excellent capacity retention upon cycling. On the other hand, LiNi 0.33 Mn 0.33 Co 0.33 O 2 (NMC111) synthesized by SCR exhibits an initial discharge capacity of about 208 mAh g -1 in the potential range of 2.3-4.9 V, which decreases to a value of 130 mAh g -1 after only 50 cycles. In turn, the multiphase structure of LiNi 0.33 Mn 0.54 Co 0.13 O 2 seems to stabilize the behavior of this cathode material even when polarized to high potentials. LiNi 0.33 Mn 0.54 Co 0.13 O 2 shows superior retention of average discharge voltage upon cycling as compared to that of LiNi 0.33 Mn 0.33 Co 0.33 O 2 when cycled in a wide potential range. Overall, ChemElectroChem 10.1002/celc.201500339 2 LiNi 0.33 Mn 0.54 Co 0.13 O 2 can be considered as a promising low cobalt content cathode material for Li ion batteries.
2006
The uniform layered Li[Ni 1/3 Co 1/3 Mn 1/3 ]O 2 cathode material for lithium ion batteries was prepared by using (Ni 1/3 Co 1/3 Mn 1/3)(OH) 2 synthesized by a liquid phase co-precipitation method as precursor. The effects of calcination temperature and time on the structural and electrochemical properties of the Li[Ni 1/3 Co 1/3 Mn 1/3 ]O 2 were systemically studied. XRD results revealed that the optimal prepared conditions of the layered Li[Ni 1/3 Co 1/3 Mn 1/3 ]O 2 were 850 • C for 18 h. Electrochemical measurement showed that the sample prepared under the above conditions has the highest initial discharge capacity of 162.1 mAh g −1 and the smallest irreversible capacity loss of 9.2% as well as stable cycling performance at a constant current density of 16 mA g −1 between 3 and 4.3 V versus Li at room temperature.
Journal of The Electrochemical Society, 2016
Micro-nano structured LiFe 1-x Mn x PO 4 /C (0 ≤ x ≤ 0.05) cathodes were prepared by spray drying, followed by calcination at 700 °C. The spherical LiFe 1-x Mn x PO 4 /C (0 ≤ x ≤ 0.05) particles with the size of 0.5 to 5.0 μm are composed of lots of nanoparticles of 20 to 30 nm, and have the well-developed interconnected pore structure. In contrast, when Mn doping content is 3 mol% (x=0.03), the LiFe 0.97 Mn 0.03 PO 4 /C demonstrates maximum specific surface area of 31.30 m 2 /g, more uniform pore size and relatively better electrochemical performance. The initial discharge capacities are 161.59, 157.04 and 153.13 mAh/g at a discharge rate of 0.2, 0.5 and 1 C, respectively. Meanwhile, the discharge capacity retentions are ~ 100% after 120 cycles. The improved electrochemical performance should be attributed to higher specific surface, smaller polarization voltage, and a high Li + diffusion rate due to the micro-nano porous structure and lattice expansion