Nanocrystalline LiNi0.4Mn0.4Co0.2O2 cathode for lithium-ion batteries (original) (raw)
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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.
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.
Chemical Science Transactions, 2017
LiNi 1/3 Co 1/3 Mn 1/3 O 2 was synthesized by solid state reaction method and the effect of calcination temperature on characteristics of LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathode was investigated. Thermal analysis reveals the temperature dependence of the materials properties. The phase composition, micro-morphology, elemental analysis and Wyckoff sites of the products were characterized by xray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectra (EDS) and Fourier transform infrared (FTIR) respectively. The results of XRD pattern possessed the α-NaFeO 2 structure of the hexagonal system (space group m R 3). The morphological features of the powders were characterized by scanning electron microscopy (SEM). The EDS spectra confirm the presence of Ni, Co, Mn and O in the compound. The FT-IR spectroscopic data reveals that the structure of the oxide lattice constituted by LiO 6 , NiO 6, CoO 6 and MnO 6 octahedral. The variation of the ac conductivity, dielectric constant and electric modulus as function of frequency and temperature was determined to study the electrical properties of the synthesized sample. Electron spin resonance (ESR) was carried out to study the magnetic properties as well. From this study, we conclude that the layered LiNi 1/3 Co 1/3 Mn 1/3 O 2 material prepared by solid-state reaction method at 900 °C for 18h is promising next-generation cathode material for lithium ion batteries.
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.
Journal of Power Sources, 2012
First-principles calculations are used to analyze the phase stability, formation energy, and Li intercalation potential for a series of layered cathode materials. The calculations show LiNi 0.66 Co 0.17 Mn 0.17 O 2 as a promising cathode for lithium-ion batteries. The layer-structured LiNi 0.66 Co 0.17 Mn 0.17 O 2 is prepared via wet chemical route, followed by annealing at 1123 K and characterized using powder X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The characterization techniques reveal single-phase LiNi 0.66 Co 0.17 Mn 0.17 O 2 with highly ordered structure. Galvanostatic chargeedischarge curves recorded at 1C show the discharge capacity of ca. 167 mAh g À1 and good cyclic performance for 25 cycles.
Structural, electrical and electrochemical studies of LiNi 0.4 M 0.1 Mn 1.5 O 4 (M = Co, Mg) solid solutions for lithium ion battery Abstract. The LiNi 0.4 M 0.1 Mn 1.5 O 4 (M = Co, Mg) solid solutions are synthesized by citric acid assisted sol–gel method and characterized by using TG/DTA, XRD, FTIR, EPR and SEM. The electrochemical characterization is carried out using CR-2032 coin type cell configuration. The cyclic voltammogram shows two pairs of redox current peaks, 4.35/3.80 V and 4.90/4.37 V vs. Li in a typical case of Co-doped sample, ascribed to two-step reversible intercalation of Li. A.c.-impedance (Nyquist plot) shows high frequency semicircle and a sloping line in the low-frequency region. The semicircle is ascribed to Li-ion migration through interface from the surface layer of the particles to electrolyte. The LiNi 0.4 Co 0.1 Mn 1.5 O 4 shows reasonably good capacity retention in 20 cycles of galvanostatic charge/discharge cycling. Keywords. Lithium ion batteries; positive electrode; LiNi 0.5 Mn 1.5 O 4-based spinels; sol–gel method; charge/discharge.
The layered lithium-metal oxides are promising cathode materials for Li-ion batteries. Nevertheless, their widespread applications have been limited by the high cost, complex process, and poor stability resulting from the Ni 2+ /Li + mixing. Hence, we have developed a facile one-spot method combining glucose and urea to form a deep eutectic solvent, which could lead to the homogeneous distribution and uniform mixing of transition-metal ions at the atomic level. LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) polyhedron with high homogeneity could be obtained through in situ chelating Ni 2+ , Co 3+ , and Mn 4+ by the amid groups. The prepared material exhibits a relatively high initial electrochemical property, which is due to the unique single-crystal hierarchical porous nano/microstructure, the polyhedron with exposed active surfaces, and the negligible Ni 2+ /Li + mixing level. This one-spot approach could be expanded to manufacture other hybrid transition-metal-based cathode materials for batteries.
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, 2006
LiNi 0.5 Mn 0.4 M 0.1 O 2 (M = Li, Mg, Al, Co) compound was prepared by a solid-state reaction, and its structural, morphological and electrochemical properties were characterized by XRD, SEM, charge-discharge tests and EIS. The impacts of alien ion introduction on the structural, morphological and electrochemical properties of LiNi 0.5 Mn 0.5 O 2 depend on the dopants. The substitution of Li, Mg, and Co for Mn can enlarge the particle size and improve the crystallinity. LiNi 0.5 Mn 0.4 Li 0.1 O 2 and LiNi 0.5 Mn 0.4 Co 0.1 O 2 show increased reversible capacities as well as upgraded rate capabilities. LiNi 0.5 Mn 0.4 Li 0.1 O 2 exhibits a retentive capacity of about 200 mAh g −1 at 50 • C.