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1.
LiMn2O4 has been considered a promising cathode material for lithium-ion batteries in electric vehicles. However, there are still
a number of problems of severe capacity fading before any materials modifications. Among all doped LiMn2O4, spinel LiNi0.5Mn1.5O4 material is seen as a potential cathode material for use in electric vehicles and energy storage systems in the future because
of its high working potential (4.7 V), high energy density (the energy density of LiNi0.5Mn1.5O4 is 20% higher than that of LiCoO2), acceptable stability, and good cycling performance. In the presented paper, the structure and electrochemical performance
of doped LiNi0.5Mn1.5O4 are reviewed. The rate capability, rate performance and cyclic life of various doped LiNi0.5Mn1.5O4 materials are described. This review also focuses on the present status of doped LiNi0.5Mn1.5O4, then on its near future developments. 相似文献
2.
Juntian Fan Tao Dong Daliang Fang Xuefeng Li Xian’en Mo Kaihua Wen Shimou Chen Suojiang Zhang 《Ionics》2018,24(10):2965-2972
In this work, Li2ZrF6, a lithium salt additive, is reported to improve the interface stability of LiNi0.5Mn1.5O4 (LNMO)/electrolyte interface under high voltage (4.9 V vs Li/Li+). Li2ZrF6 is an effective additive to serve as an in situ surface coating material for high-voltage LNMO half cells. A protective SEI layer is formed on the electrode surface due to the involvement of Li2ZrF6 during the formation of SEI layer. Charge/discharge tests show that 0.15 mol L?1 Li2ZrF6 is the optimal concentration for the LiNi0.5Mn1.5O4 electrode and it can improve the cycling performance and rate property of LNMO/Li half cells. The results obtained by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) demonstrate that Li2ZrF6 can facilitate the formation of a thin, uniform, and stable solid electrolyte interface (SEI) layer. This layer inhibits the oxidation decomposition of the electrolyte and suppresses the dissolution of the cathode materials, resulting in improved electrochemical performances. 相似文献
3.
Nanosized LiNi0.5Mn1.5O4 spinels with the uniform average particle size of about 80–100 nm were synthesized by a high-oxidation-state manganese sol–gel method. It indicates that the resulting nanosized LiNi0.5Mn1.5O4 materials not only have a phase-pure cubic spinel structure without any impurity but also have a good dispersion even without any physical treatment. Besides, the cell based upon the resulting nanosized LiNi0.5Mn1.5O4 materials shows good cycle stability and ratio performance. It suggests that the novel method would be helpful for the synthesis and application of LiNi0.5Mn1.5O4 cathode. 相似文献
4.
Fluoroethylene carbonate (FEC) is investigated as the electrolyte additive to improve the electrochemical performance of high voltage LiNi0.6Co0.2Mn0.2O2 cathode material. Compared to LiNi0.6Co0.2Mn0.2O2/Li cells in blank electrolyte, the capacity retention of the cells with 5 wt% FEC in electrolytes after 80 times charge-discharge cycle between 3.0 and 4.5 V significantly improve from 82.0 to 89.7%. Besides, the capacity of LiNi0.6Co0.2Mn0.2O2/Li only obtains 12.6 mAh g?1 at 5 C in base electrolyte, while the 5 wt% FEC in electrolyte can reach a high capacity of 71.3 mAh g?1 at the same rate. The oxidative stability of the electrolyte with 5 wt% FEC is evaluated by linear sweep voltammetry and potentiostatic data. The LSV results show that the oxidation potential of the electrolytes with FEC is higher than 4.5 V vs. Li/Li+, while the oxidation peaks begin to appear near 4.3 V in the electrolyte without FEC. In addition, the effect of FEC on surface of LiNi0.6Co0.2Mn0.2O2 is elucidated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The analysis result indicates that FEC facilitates the formation of a more stable surface film on the LiNi0.6Co0.2Mn0.2O2 cathode. The electrochemical impedance spectroscopy (EIS) result evidences that the stable surface film could improve cathode electrolyte interfacial resistance. These results demonstrate that the FEC can apply as an additive for 4.5 V high voltage electrolyte system in LiNi0.6Co0.2Mn0.2O2/Li cells. 相似文献
5.
Structural and magnetic properties of LiNi0.5Mn1.5O4 and LiNi0.5Mn1.5O4-δ spinels: A first-principles study
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<正>Structural and magnetic properties of LiNi0.5Mn1.5O4 and LiNi0.5Mn1.5O4-δ are investigated using densityfunctional theory calculations.Results indicate that nonstoichiometric LiNi0.5Mn1.5O4-δ and stoichiometric LiNi0.5Mn1.5O4 exhibit two different structures,i.e.,the face-centred cubic(Fd-3m) and primitive,or simple,cubic (P4332) space groups,respectively.It is found that the magnetic ground state of LiNi0.5Mn1.5O4(P4332 and Fd-3m) is a ferrimagnetic state in which the Ni and Mn sublattices are ferromagnetically ordered along the[110]direction whereas they are antiferromagnetic with respect to each other.We demonstrate that it is the presence of an O-vacancy in LiNi0.5Mn1.5O4-δ with the Fd-3m space group that results in its superior electronic conductivity compared with LiNi0.5Mn1.5O4 with the P4332 space group. 相似文献
6.
Spinel LiNi0.5Mn1.5O4 cathode materials with different lithium excess amount (0, 2%, 6%, 10%) were synthesized by a facile solid-state method. The effect of lithium excess amount on the microstructure, morphology, and electrochemical properties of LiNi0.5Mn1.5O4 materials was systematically investigated. The results show that the lithium excess amount does not change the particle morphology and size obviously; thus, the electrochemical properties of LiNi0.5Mn1.5O4 are mainly determined by structural characteristics. With the increase of lithium excess amount, the cation disordering degree (Mn3+ content) and phase purity first increase and then decrease, while the cation mixing extent has the opposite trend. Among them, the LiNi0.5Mn1.5O4 material with 6% lithium excess amount exhibits higher disordering degree and lower impurity content and cation mixing extent, thus leading to the optimum electrochemical properties, with discharge capacities of 125.0, 126.1, 124.2, and 118.9 mAh/g at 0.2-, 1-, 5-, and 10-C rates and capacity retention rate of 96.49% after 100 cycles at 1-C rate. 相似文献
7.
High-voltage spinel LiNi0.5Mn1.5O4 has been considered one of the most promising cathode materials for lithium-ion power batteries used in electrical vehicles (EVs) or hybrid electrical vehicles (HEVs) because the high voltage plateau at around 4.7 V makes its energy density (658 Wh kg?1) 30 and 25 % higher than that of conventional pristine spinel LiMn2O4 (440 Wh kg?1) or olivine LiFePO4 (500 Wh kg?1) materials, respectively. Unfortunately, LiNi0.5Mn1.5O4-based batteries with LiPF6-based carbonate electrolytes always suffer from severe capacity deterioration and poor thermostability because of the oxidization of organic carbonate solvents and decomposition of LiPF6, especially at elevated temperatures and water-containing environment. The major goal of this review is to highlight the recent advancements in the development of advanced electrolytes for improving the cycling stability and rate capacity of LiNi0.5Mn1.5O4-based batteries. Finally, an insight into the future research and further development of advanced electrolytes for LiNi0.5Mn1.5O4-based batteries is discussed. 相似文献
8.
AlF3-coating is attempted to improve the performance of LiNi0.5Mn1.5O4 cathode materials for Li-ion batteries. The prepared powders are characterized by scanning electron microscope, powder X-ray
diffraction, charge/discharge, and impedance. The coated LiNi0.5Mn1.5O4 samples show higher discharge capacity, better rate capability, and higher capacity retention than the uncoated samples.
Among the coated samples, 1.0 mol% AlF3-coated sample shows highest capacity after charge–discharged at 30 mA/g for 3 cycles, but 4.0 mol% coated sample exhibits
the highest capacity and cycling stability when cycled at high rate of 150 and 300 mA/g. The 40th cycle discharge capacity
at 300 mA/g current still remains 114.8 mAh/g for 4.0 mol% AlF3-coated LiNi0.5Mn1.5O4, while only 84.3 mAh/g for the uncoated sample. 相似文献
9.
Structure and insertion properties of disordered and ordered LiNi0.5Mn1.5O4 spinels prepared by wet chemistry 总被引:1,自引:0,他引:1
We present the synthesis, characterization, and electrode behavior of LiNi0.5Mn1.5O4 spinels prepared by the wet-chemical method via citrate precursors. The phase evolution was studied as a function of nickel substitution and upon intercalation and deintercalation of Li ions. Characterization methods include X-ray diffraction, SEM, Raman, Fourier transform infrared, superconducting quantum interference device, and electron spin resonance. The crystal chemistry of LiNi0.5Mn1.5O4 appears to be strongly dependent on the growth conditions. Both normal-like cubic spinel [Fd3m space group (SG)] and ordered spinel (P4
1
32 SG) structures have been formed using different synthesis routes. Raman scattering and infrared features indicate that the vibrational mode frequencies and relative intensities of the bands are sensitive to the covalency of the (Ni, Mn)-O bonds. Scanning electron microscopy (SEM) micrographs show that the particle size of the LiNi0.5Mn1.5O4 powders ranges in the submicronic domain with a narrow grain-size distribution. The substitution of the 3d8 metal for Mn in LiNi0.5Mn1.5O4 oxides is beneficial for its charge–discharge cycling performance. For a cut-off voltage of 3.5–4.9 V, the electrochemical capacity of the Li//LiNi0.5Mn1.5O4 cell is ca. 133 mAh/g during the first discharge. Differences and similarities between LiMn2O4 and LiNi0.5Mn1.5O4 oxides are discussed. 相似文献
10.
The thermodynamic stability is a very important quantity for the electrode materials, because it is not only related to the electrochemical performances of the materials but also the safety issue of the cells. To evaluate the thermodynamic stability of Li x Ni0.5Mn1.5O4 (x = 0, 1), the formation enthalpies from elemental phases and oxides were obtained. The values for LiNi0.5Mn1.5O4 were calculated to be ?1341.10 and ?141.84 kJ mol?1, while those for Ni0.5Mn1.5O4 were ?949.11 and ?49.21 kJ mol?1. These values are much more negative than those of LiCoO2 and LiNiO2 compounds, indicating that the thermodynamic stability of Li x Ni0.5Mn1.5O4 is better than the two classic compounds. To clarify the microscopic origin, the density of states, magnetic moments, and bond orders were systematically investigated. The results showed that the excellent thermodynamic stability of LiNi0.5Mn1.5O4 is attributed to the absence of Jahn-Teller distortions, strong electrostatic interactions of Li–O ionic bond, and strong Ni–O/Mn–O ionic-covalent mixing bonds. After lithium extraction, the disappearance of the pure Li–O bonds leads to an increase of formation enthalpy, indicating a decreasing thermodynamic stability for Ni0.5Mn1.5O4 with respect to LiNi0.5Mn1.5O4. 相似文献
11.
Yuan Xue Li-Li Zheng Zhen-Bo Wang Yi Han Fu-Da Yu Yu-Xiang Zhou 《Journal of nanoparticle research》2018,20(9):257
The high-voltage spinel is a promising cathode material in next generation of lithium-ion batteries. Samples LiNi0.5???xMn1.5?+?xO4 (x?=?0, 0.05, 0.1) are synthesized by a simple co-precipitation method, in which pH value and temperature conditions do not need control. In the simple co-precipitation method, NaHCO3 solution is poured into transition metal solution to produce precursor. Ni and Mn are distributed uniformly in the products. The as-prepared samples are composed of ~?200 nm primary particles. Samples LiNi0.5???xMn1.5?+?xO4 (x?=?0, 0.05, 0.1) are also tested to study the effects of different Ni/Mn ratios. Sample LiNi0.5Mn1.5O4 delivers discharge capacities of 130 mAh g?1 at 0.2 C. The decreasing of Ni/Mn ratio in samples reduces specific capacity. With the decreasing of Ni/Mn ratios in spinel, amount of Mn3+ are increased. Attributed to its high Mn3+ contents, sample LiNi0.4Mn1.6O4 delivers the highest discharge capacity of 106 mAh g?1 at a large current density of 15 C, keeping 84.5% of that at 0.2 C rate. With the increasing of Ni/Mn ratios in spinel, cycling performance is improved. Sample LiNi0.5Mn1.5O4 shows the best cycling stability, keeping 94.4% and 90.4% of the highest discharge capacities after 500 cycles at 1 C and 1000 cycles at 5 C. 相似文献
12.
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. 相似文献
13.
LiNi0.5Mn1.5O4 cathode material was prepared by electrospinning using lithium hydroxide, manganese acetate, nickel acetate, acetic acid, ethanol, and poly(vinyl pyrrolidone) as raw materials. The effect of calcination temperature on the structure, morphology, and electrochemical properties was investigated. XRD results indicate that the LiNi0.5Mn1.5O4 composite is well crystallized as a spinel structure at calcination temperature of 650 °C for 3 h. SEM results reveal that this composite has a nanofiber shape with average size of about 300–500 nm. Electrochemical performance tests reveal that this composite shows the initial discharge capacity of 127.8 and 105 mAhg?1 at 0.1 and 3 C rates, respectively, and exhibits good cycling performance. 相似文献
14.
Ahmed M. Hashem Ashraf E. Abdel Ghany Kristian Nikolowski Helmut Ehrenberg 《Ionics》2010,16(4):305-310
LiNi0.5Mn0.5O2 powder was synthesized by a coprecipitation method. LiOH.H2O and coprecipitated [(Ni0.5Mn0.5)C2O4] precursors were mixed carefully together and then calcined at 900°C. Surface modified cathode materials were obtained by
coating LiNi0.5Mn0.5O2 with a thin layer of amorphous carbon using table sugar and starch as carbon source. Both parent and carbon-coated samples
have the characteristic layered structure of LiNi0.5Mn0.5O2 as estimated from X-ray diffractometry measurements. Transmission electron microscope showed the presence of C layer around
the prepared particles. TGA analysis emphasized and confirmed the presence of C coating around LiNi0.5Mn0.5O2. It is obvious that the carbon coating appears to be beneficial for the electrochemical performance of the LiNi0.5Mn0.5O2. A capacity of about 150 mAh/g is delivered in the voltage range 2.5–4.5 V at current density C/15 for carbon coated LiNi0.5Mn0.5O2 in comparison with about 165 mAh/g obtained for carbon free LiNi0.5Mn0.5O2 at the same current density and voltage window. About 92% and 82% capacity retention was obtained at 50th cycle for coated
LiNi0.5Mn0.5O2 using sucrose and starch, respectively; whereas, 75% was retained after only 30th cycle for carbon free LiNi0.5Mn0.5O2. This improvement is mainly attributed to the presence of thin layer of carbon layer that encapsulate the nanoparticles and
improve the conductivity and the electrochemical performance of LiNi0.5Mn0.5O2. 相似文献
15.
Xiaofeng Zhang Honghe Zheng Vincent Battaglia Richard L. Axelbaum 《Proceedings of the Combustion Institute》2011,33(2):1867-1874
The lithium transition metal oxide LiNi0.5Mn1.5O4 with an space group (SG) structure has shown great potential as a cathode material for 5 V lithium-ion rechargeable-batteries. In this work, a flame-assisted spray technology (FAST) was developed to produce nanostructured LiNi0.5Mn1.5O4 powder in a continuous manner. The as-synthesized powder had a uniform morphology, was spherical in shape and had a nanocrystalline structure, as observed by SEM and TEM. The XRD pattern of the as-synthesized powder matched the spectrum of spinel-LiNi0.5Mn1.5O4. The average grain size was about 16 nm, as calculated by XRD. However, XRD also indicated the impurity Mn2NiO4 in the powder. By varying flame temperature, it was possible to show that the impurity was formed due to the high temperature of the flame. While flame temperature was minimized by lowering the H2/N2 ratio, it was not possible to completely eliminate Mn2NiO4 from the as-synthesized powder. After annealing at 800 °C for 2 h, the impurity was eliminated, and the XRD pattern of the powder indicated a pure-phase spinel structure with an SG. The electrochemical performance of the flame-synthesized LiNi0.5Mn1.5O4 powder was tested in coin-type test batteries that were charged and discharged at constant current under a 5 V potential. The test cells showed the characteristic voltage plateaus of spinel-LiNi0.5Mn1.5O4 ( SG). The material proved to be electrochemically active as a cathode material for lithium-ion rechargeable-batteries. 相似文献
16.
Review of 5-V electrodes for Li-ion batteries: status and trends 总被引:1,自引:0,他引:1
Lithium-ion batteries have dominated the battery industry for the past several years in portable electronic devices due to their high volumetric and gravimetric energy densities. The success of these batteries in small-scale applications translates to large-scale applications, with an important impact in the future of the environment by improving energy efficiency and reduction of pollution. We present the progress that allows several lithium-intercalation compounds to become the active cathode element of a new generation of Li-ion batteries, namely the 5-V cathodes, which are promising to improve the technology of energy storage and electric transportation, and address the replacement of gasoline engine by meeting the increasing demand for green energy power sources. The compounds considered here include spinel LiNi0.5Mn1.5O4 and its related doped-structures, olivine LiCoPO4, inverse spinel LiNiVO4 and fluorophosphate Li2CoPO4F. LiNi0.5Mn1.5O4 thin films, nanoscale prepared materials and surface-modified cathode particles are also considered. Emphasis is placed on the quality control that is needed to guarantee the reliability and the optimum electrochemical performance of these materials as the active cathode element of Li-ion batteries. The route to increase the performance of Li-ion batteries with the other members of the family is also discussed. 相似文献
17.
Vinyl ethylene carbonate (VEC) is investigated as an electrolyte additive to improve the electrochemical performance of LiNi0.4Mn0.4Co0.2O2/graphite lithium-ion battery at higher voltage operation (3.0–4.5 V) than the conventional voltage (3.0–4.25 V). In the voltage range of 3.0–4.5 V, it is shown that the performances of the cells with VEC-containing electrolyte are greatly improved than the cells without additive. With 2.0 wt.% VEC addition in the electrolyte, the capacity retention of the cell is increased from 62.5 to 74.5 % after 300 cycles. The effects of VEC on the cell performance are investigated by cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS), x-ray powder diffraction (XRD), energy dispersive x-ray spectrometry (EDS), scanning electron microscopy (SEM), and attenuated total reflectance-Fourier transform infrared (ATR-FTIR). The results show that the films electrochemically formed on both anode and cathode, derived from the in situ decomposition of VEC at the initial charge–discharge cycles, are the main reasons for the improved cell performance. 相似文献
18.
Li1.1Ni0.25Mn0.75O2.3 and Li1.5Ni0.25Mn0.75O2.5 have been synthesized by co-precipitation method. The effect of the LiNi0.5Mn1.5O4 spinel structure on physical and electrochemical properties is discussed through the characterizations of X-ray diffraction (XRD), scanning electron microscopy, high-resolution transmission electron microscopy, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and electrochemical performance tests. The LiNi0.5Mn1.5O4 spinel structure is detected in the XRD pattern, TEM image, first discharge, and CV curves of the Li1.1Ni0.25Mn0.75O2.3 electrode. The rate, cyclic performance, and first coulomb efficiency of Li1.1Ni0.25Mn0.75O2.35 are higher than those of Li1.5Ni0.25Mn0.75O2.5. The first coulomb efficiencies of Li1.1Ni0.25Mn0.75O2.3 and Li1.5Ni0.25Mn0.75O2.5 are 86.2 and 74.7 %, and the capacity retentions are 98.7 and 94.1 % after 50 cycles, respectively. EIS results indicate that the charge-transfer reaction resistance of Li1.1Ni0.25Mn0.75O2.3 is lower than that of Li1.5Ni0.25Mn0.75O2.5, which is responsible for the better rate capacity of Li1.1Ni0.25Mn0.75O2.3. 相似文献
19.
LiNi0.5Mn1.5O4 was synthesized as a cathode material for Li-ion batteries by a sonochemical reaction followed by annealing, and was characterized by XRD, SEM, HRTEM and Raman spectroscopy in conjunction with electrochemical measurements. Two samples were prepared by a sonochemical process, one without using glucose (sample-S1) and another with glucose (sample-S2). An initial discharge specific capacity of 130 mA h g−1 is obtained for LiNi0.5Mn1.5O4 at a relatively slow rate of C/10 in galvanostatic charge–discharge cycling. The capacity retention upon 50 cycles at this rate was around 95.4% and 98.9% for sample-S1 and sample-S2, respectively, at 30 °C. 相似文献
20.
This paper describes the preparation and characterization of a high-voltage lithium-ion battery based on Sn-decorated reduced graphene oxide and LiNi0.5Mn1.5O4 as the anode and cathode active materials, respectively. The Sn-decorated reduced graphene oxide is prepared using a microwave-assisted hydrothermal synthesis method followed by reduction at high temperature of a mixture of (C6H5)2SnCl2 and graphene oxide. The so-obtained anode material is characterized by thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and electron diffraction spectroscopy. The LiNi0.5Mn1.5O4 is a commercially available product. The two materials are used to prepare composite electrodes, and their electrochemical properties are investigated by galvanostatic charge/discharge cycles at various current densities in lithium cells. The electrodes are then used to assemble a high-voltage lithium-ion cell, and the cell is tested to evaluate its performance as a function of discharge rate and cycle number. 相似文献