Nickel Manganese Oxide Research Articles

Corona Yank in Edged Cathode Particles for Li-Ion Batteries.

In a heuristic endeavor based on electrostatics-dynamics considerations, an attempt has been made to explain the significant enhancement (∼20%) observed in initial capacity for the as-synthesized, sharp-edged cathode particles of lithium nickel manganese cobalt oxide, and lithium nickel manganese oxide cathode systems which are considered here as illustrative examples. Also, the impressive capacity retention (∼90%) observed for the milled blend of these, comprising smooth surfaced particles with cells made using respective cathode particles, has been explained. Enhancement in initial capacity observed for the edged particles can be squarely attributed to a corona-gain process. On the contrary, impressive capacity retention possible for the milled blend (of near-spherical particles) can be rationalized in terms of the absence of predominant energy drain encountered while shuttling charges across edges of the as-synthesized cathode particles, a process described as corona yank.

Effect of surface modification and oxygen deficiency on intercalation property of lithium nickel manganese oxide in an all-solid-state battery

LiNbO3-coated LiNi0.5Mn1.5O4 powders were synthesized by a sol–gel method, and their intercalation property as a cathode material was investigated using all-solid-state batteries with Li10GeP2S12 solid electrolyte and In–Li metal anode. The LiNbO3 coating delivered reversible lithium intercalation of LiNi0.5Mn1.5O4 through an electrochemical interface with the Li10GeP2S12. Oxygen-deficient LiNi0.5Mn1.5O4−δ with a higher electronic conductivity than LiNi0.5Mn1.5O4 improved the intercalation activity. An all-solid-state battery consisting of 3wt.%-LiNbO3-coated LiNi0.5Mn1.5O4−δ/Li10GeP2S12/In–Li exhibited a discharge capacity of 80mAhg−1 at the first cycle with an average discharge voltage of 4.1V (vs. In-Li), which demonstrates the possibility of 5V class all-solid-state batteries with a high voltage spinel cathode.

Effect of Sodium Content on the Reversible Lithium Intercalation into Sodium-Deficient Cobalt–Nickel–Manganese Oxides NaxCo1/3Ni1/3Mn1/3O2 (0.38 ≤ x ≤ 0.75) with a P3 Type of Structure

Layered lithium transition metal oxides with optimized nickel–manganese content are nowadays of primary interest as electrode materials for lithium ion batteries, since they are able to deliver a high capacity at a low cost. Herein we report a new class of less expensive cathode materials, which comprise sodium-deficient cobalt–nickel–manganese oxides NaxCo1/3Ni1/3Mn1/3O2 characterized with a layered structure and broad concentration range of sodium solubility. NaxCo1/3Ni1/3Mn1/3O2 oxides are obtained by thermal decomposition of mixed acetate–oxalate precursors, followed by thermal annealing between 700 and 800 °C. In the concentration range of 0.33 < x ≤ 0.75, NaxCo1/3Ni1/3Mn1/3O2 oxides assume a layered structure with a three-layer stacking (i.e., P3 type of structure). Based on electron paramagnetic resonance spectroscopy operating in the X-band (9.4 GHz), it is found that the charge compensation of Na deficiency is achieved by preferential oxidation of Ni2+ to Ni3+ and Ni4+, while Co and Mn ions retain their oxidation state of 3+ and 4+ within the whole concentration range. The electrochemical performance of NaxCo1/3Ni1/3Mn1/3O2 in model lithium cells is simply controlled by the amount of sodium content in the pristine compositions: a higher reversible capacity is achieved for sodium-rich oxides (i.e., 0.75 ≥ x ≥ 0.67), while sodium-poor oxides (i.e., 0.38 ≤ x ≤ 0.50) display a lower reversible capacity and improved cycling stability. The mechanism of the lithium intercalation into NaxCo1/3Ni1/3Mn1/3O2 is discussed on the basis of ex situ XRD, HRTEM, and X-ray photoelectron spectroscopy analyses.

Hollow spherical LiNi0.5Mn1.5O4 built from polyhedra with high-rate performance via carbon nanotube modification

Lithium nickel manganese oxide spinel (LiNi0.5Mn1.5O4, LNMO) has attracted much attention as the cathode material for rechargeable lithium-ion batteries due to its high energy density and low cost. However, the short cycle life and poor high-rate capability hinder its commercialization. In this study, we synthesized hollow spherical LNMO built from polyhedral particles. The LNMO hollow structure guarantees sufficient contact with electrolyte and rapid diffusion of lithium ions. To enhance the conductivity, we use carbon nanotubes (CNTs) to modify the surface of the cathode. After CNT modification, the LNMO hollow structure manifests outstanding cycling stability and high-rate capability. It delivers a discharge capacity of 127 mA h g−1 at 5 C, maintaining 104 mA h g−1 after 500 cycles. Even at a high rate of 20 C, a capacity of 121 mA h g−1 can be obtained. The excellent electrochemical performance is ascribed to the unique structure and the enhanced conductivity through CNT modification. It is demonstrated that the CNT-modified hollow spherical LNMO is a promising cathode for lithium ion batteries.

Tailoring the pseudocapacitive behavior of electrochemically deposited manganese-nickel oxide films

Manganese-nickel mixed oxide thin films were deposited by anodic electrodeposition on stainless steel substrate from an acetate solution using a potentiodynamic technique, at scan rate of 100mVs−1 and room temperature. The effect of electrolyte pH, varied in the range from 4 to 7, on composition, morphology and capacitance behavior of oxide thin films was investigated. The nickel content in the oxide increased with increasing deposition pH, allowing to investigate the effect of the oxide composition on the capacitive behavior of as-grown manganese-nickel mixed oxides. Oxide films deposited from the electrolyte at pH 6, having a composition close to Ni0.10Mn0.90Ox showed the highest specific capacitance and the lowest charge transfer resistance. After annealing, the oxide had a complex structure of composite nature, consisting of intermixed amorphous and nanocrystalline phases. A birnessite type oxide with turbostratic disorder was identified as the major phase, in the presence of nickel hydroxide as a finely dispersed second phase. Annealing caused a drastic reduction of the charge transfer resistance and a limited increase of the specific capacitance, probably as the result of diverging effects on oxide properties, i.e. enhanced conductivity and porosity sintering. Cycle life testing of this material revealed a 25% increase of the specific capacitance over 5,000 cycles to a final value of 225Fg−1 (1M Na2SO4, 50mVs−1, 0.11mgcm−2 mass loading).

Enhanced photoelectrochemical performance of electrodeposited hematite films decorated with nanostructured NiMnOx

In the present work, we report a novel nickel-manganese oxide (NiMnOx) decorated hematite (α-Fe2O3) photoanode for efficient water splitting in a photoelectrochemical (PEC) cell.

Synthesis, Optical Characterization, and Thermal Decomposition of Complexes Based on Biuret Ligand

Four complexes were synthesized in methanol solution using nickel acetate or nickel chloride, manganese acetate, manganese chloride, and biuret as raw materials. The complexes were characterized by elemental analyses, UV, FTIR, Raman spectra, X-ray powder diffraction, and thermogravimetric analysis. The compositions of the complexes were [Ni(bi)2(H2O)2](Ac)2·H2O (1), [Ni(bi)2Cl2] (2), [Mn(bi)2(Ac)2]·1.5H2O (3), and [Mn(bi)2Cl2] (4) (bi = NH2CONHCONH2), respectively. In the complexes, every metal ion was coordinated by oxygen atoms or chlorine ions and even both. The nickel and manganese ions were all hexacoordinated. The thermal decomposition processes of the complexes under air included the loss of water molecule, the pyrolysis of ligands, and the decomposition of inorganic salts, and the final residues were nickel oxide and manganese oxide, respectively.

Nanowires Nickel Oxide and Nanospherical Manganese Oxide Synthesized via Low Temperature Hydrothermal Technique for Hydrogen Peroxide Sensor

Binary catalyst nickel oxides (NiO) and manganese oxides (MnO) were prepared individually via hydrothermal route. The catalysts were characterized by scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET) analysis, cyclic voltammetry (CV), and amperometry. Morphology studies revealed physical structure of nanowires nickel oxide and spherical manganese oxide with estimated length of 0.3–2.3 μm and diameter of 0.2–0.8 μm, respectively. Surface areas obtained for nickel oxide and manganese oxide were 68.9 m2 g−1and 45.2 m2 g−1, respectively. Cyclic voltammetry exhibits electrochemical responses corresponding to the electrode surfaces. The linear responses of the binary catalyst modified gold electrodes with NiO-MnO were observed in the concentration range from 31.8 μM to 0.5 mM with the detection limit of 62.5 μM.

Preparation of lithium nickel manganese oxide cathode material for 5V-class high-voltage batteries by a microwave heating method

Preparation of lithium nickel manganese oxide cathode material for 5V-class high-voltage batteries by a microwave heating method

In Situ Carbon Coated LiNi0.5Mn1.5O4 Cathode Material Prepared by Prepolymer of Melamine Formaldehyde Resin Assisted Method

Carbon coated spinel LiNi0.5Mn1.5O4 were prepared by spray-drying using prepolymer of melamine formaldehyde resin (PMF) as carbon source of carbon coating layer. The PMF carbon coated LiNi0.5Mn1.5O4 was characterized by XRD, SEM, and other electrochemical measurements. The as-prepared lithium nickel manganese oxide has the cubic face-centered spinel structure with a space group of Fd3m. It showed good electrochemical performance as a cathode material for lithium ion battery. After 100 discharge and charge cycles at 0.5 C rate, the specific discharge capacity of carbon coated LiNi0.5Mn1.5O4 was 130 mAh·g−1, and the corresponding capacity retention was 98.8%. The 100th cycle specific discharge capacity at 10 C rate of carbon coated LiNi0.5Mn1.5O4 was 105.4 mAh·g−1, and even the corresponding capacity retention was 95.2%.

Synthesis and electrochemical properties of Li2/3Ni1/3Mn2/3O2 as a novel 5 V class positive electrode material for lithium-ion batteries

A lithium nickel manganese oxide, O3-Li2/3Ni1/3Mn2/3O2, is synthesized from the precursor, P3-Na2/3Ni1/3Mn2/3O2, by a Na+/Li+ ion exchange reaction using molten salt. Post-heating at 300, 400, 500, 600, and 700 °C is carried out for 5 h in air. The products are characterized by powder XRD, inductively coupled plasma-atomic emission spectroscopy (ICP-AES), SEM, 6Li-magic-angle-spinning-NMR, and electrochemical measurements. The charge/discharge profiles of O3-Li2/3Ni1/3Mn2/3O2, thermally treated at 500 °C, show a high-potential plateau region at 4.8 V. Furthermore, sloping voltage profiles are observed at an average voltage of 3.21 V. An initial discharge capacity of 257 mA h g−1 is obtained between 2.0 and 4.8 V with a current density of 15 mA g−1 at 25 °C. This capacity corresponds to 0.90 electron transfers per formula unit. This study shows that Post-heating of O3-Li2/3Ni1/3Mn2/3O2 is effective to improve its electrochemical properties.

Impact of P-Doped in Spinel LiNi0.5Mn1.5O4 on Degree of Disorder, Grain Morphology, and Electrochemical Performance

LiNi0.5-xP2xMn1.5-xO4 (x = 0, 0.005, 0.01, and 0.02) submicrograins in regular octahedral shape with merely {111} surface facets and truncated octahedral shape with both {111} and {100} surface planes were obtained by the solid-state reaction method. The effect of doping P on ions arrangement, grain morphology, and the electrochemical performance of lithium nickel manganese oxide was investigated. The characterizations of X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), and selected area electron diffraction (SAED) confirm more Mn3+ ions in the structure to enhance the cationic disorder degree of LiNi0.5Mn1.5O4 after P-doping. Comparing the LiNi0.5Mn1.5O4 and LiNi0.495P0.01Mn1.495O4 samples both with regular octahedral morpology, their electrochemical performance could be remarkably improved by more disordered transition metal ions arrangement leading to higher conductivity of Li-ions and electrons. However, when the amount of P-doping further increased, the rate and cycle ability o...

Experimental and mathematical modeling of combined subchronic toxicity of nickel(II) oxide and manganese(II,III) oxide nanoparticles

Experimental and mathematical modeling of combined subchronic toxicity of nickel(II) oxide and manganese(II,III) oxide nanoparticles

Attenuation of Combined Nickel(II) Oxide and Manganese(II, III) Oxide Nanoparticles' Adverse Effects with a Complex of Bioprotectors.

Stable suspensions of NiO and Mn3O4 nanoparticles (NPs) with a mean (±s.d.) diameter of 16.7 ± 8.2 and 18.4 ± 5.4 nm, respectively, purposefully prepared by laser ablation of 99.99% pure nickel or manganese in de-ionized water, were repeatedly injected intraperitoneally (IP) to rats at a dose of 2.5 mg/kg 3 times a week up to 18 injections, either alone or in combination. A group of rats was injected with this combination with the background oral administration of a “bio-protective complex” (BPC) comprising pectin, vitamins A, C, E, glutamate, glycine, N-acetylcysteine, selenium, iodide and omega-3 PUFA, this composition having been chosen based on mechanistic considerations and previous experience. After the termination of injections, many functional and biochemical indices and histopathological features (with morphometric assessment) of the liver, spleen, kidneys and brain were evaluated for signs of toxicity. The Ni and Mn content of these organs was measured with the help of the atomic emission and electron paramagnetic resonance spectroscopies. We obtained blood leukocytes for performing the RAPD (Random Amplified Polymorphic DNA) test. Although both metallic NPs proved adversely bio-active in many respects considered in this study, Mn3O4-NPs were somewhat more noxious than NiO-NPs as concerns most of the non-specific toxicity manifestations and they induced more marked damage to neurons in the striatum and the hippocampus, which may be considered an experimental correlate of the manganese-induced Parkinsonism. The comparative solubility of the Mn3O4-NPs and NiO-NPs in a biological medium is discussed as one of the factors underlying the difference in their toxicokinetics and toxicities. The BPC has attenuated both the organ-systemic toxicity and the genotoxicity of Mn3O4-NPs in combination with NiO-NPs.

P3-Type Layered Sodium-Deficient Nickel-Manganese Oxides: A Flexible Structural Matrix for Reversible Sodium and Lithium Intercalation.

Sodium-deficient nickel-manganese oxides exhibit a layered structure, which is flexible enough to acquire different layer stacking. The effect of layer stacking on the intercalation properties of P3-Nax Ni0.5 Mn0.5 O2 (x=0.50, 0.67) and P2-Na2/3 Ni1/3 Mn2/3 O2 , for use as cathodes in sodium- and lithium-ion batteries, is examined. For P3-Na0.67 Ni0.5 Mn0.5 O2 , a large trigonal superstructure with 2√3 a×2√3 a×2 c is observed, whereas for P2-Na2/3 Ni1/3 Mn2/3 O2 there is a superstructure with reduced lattice parameters. In sodium cells, P3 and P2 phases intercalate sodium reversibly at a well-expressed voltage plateau. Preservation of the P3-type structure during sodium intercalation determines improving cycling stability of the P3 phase within an extended potential range, in comparison with that for the P2 phase, for which a P2-O2 phase transformation has been found. Between 2.0 and 4.0 V, P3 and P2 phases display an excellent rate capability. In lithium cells, the P3 phase intercalates lithium, accompanied by a P3-O3 structural transformation. The in situ generated O3 phase, containing lithium and sodium simultaneously, determines the specific voltage profile of P3-Nax Ni0.5 Mn0.5 O2 . The P2 phase does not display any reversible lithium intercalation. The P3 phase demonstrates a higher capacity at lower rates in lithium cells, whereas in sodium cells P3-Nax Ni0.5 Mn0.5 O2 operates better at higher rates. These findings reveal the unique ability of sodium-deficient nickel-manganese oxides with a P3-type structure for application as low-cost electrode materials in both sodium- and lithium-ion batteries.

Domain Modeling of Lithium-Rich Manganese Nickel Oxide By Reverse Monte Carlo Method

INTRODUCTION Lithium manganese nickel oxides with layered structures have been investigated actively in the last decade. Especially, materials with lithium-rich compositions, such as Li1.2Mn0.6Ni0.2O2, are regarded as promising candidates for a cathode active material of the lithium-ion battery, due to higher energy densities, lower costs than typical commercialized cathodes like LiCoO2-based materials. It is well-known that their electrochemical properties are affected by cation distributions in the crystals, such as a LiMn6domain in a transition-metal layer and a Ni-O domain due to a cation mixing of Li and Ni. Therefore, the domain structures have been studied recently by TEM, NMR, extended X-ray absorption fine structure (EXAFS) and so on. For deeper understanding of domain structures, we have focused on the Reverse Monte Carlo (RMC) modeling on crystals using the Bragg reflections and total scatterings simultaneously. In this work, we applied the RMC to lithium manganese nickel oxides with layered structures and then determined local (non-periodic) domain structures in intermediate range up to ca.10 Å in addition to average (periodic) host structures. EXPERIMENTAL Lithium transition-metal oxides, such as Li1.2Mn0.6Ni0.2O2, were synthesized by a coprecipitation method. Phase identifications of the samples were carried out laboratorial X-ray diffraction measurements, and the metal compositions were investigated by the inductively-coupled plasma (ICP) technique. For the reverse Monte Carlo modeling on crystals, synchrotron X-ray diffraction/total scattering patterns were measured by BL02B2 and BL04B2 installed at SPring-8, Japan. By using both the Bragg profile and structure factors S box(Q) which were degraded taking simulation-box sizes into account, we performed the RMC simulation with RMCProfile, and then analyzed domain structures of the specimens. RESULTS AND DISCUSSION X-ray diffraction and ICP measurements confirmed that the Li1.2Mn0.6Ni0.2O2 had a single phase of the Li2MnO3-type layered structure and the analytical metal composition was almost equal to the nominal value. For the purpose of a domain modeling in the crystal, we measured both the Bragg profile with high reciprocal-space resolution and the total scattering pattern with wide Q range. By using both the Bragg data and the convolved S box(Q), the RMC simulation was carried out. Figure 1 shows results of the RMC for Li1.2Mn0.6Ni0.2O2. It is demonstrated that the RMC modeling can be performed successfully. From the simulated atomic configuration, we obtained pair distribution functions g(r) and then analyzed them. As a result, it is found that there is a correlation around 4 Å in g Ni-Ni(r). This indicates that a Ni-O domain is formed in the crystal. Figure 1

Biwedge Octahedron-Shaped Li-Excess Nickel-Manganese Oxide Cathode Showing Remarkably Suppressed Potential Fade

Li-ion batteries (LIBs) are foreseen to play a very important role in energy storage for the next decade. Research for advanced Li-ion secondary batteries has been following the direction toward higher energy and power densities. Various cathode materials, such as LiCoO2, LiMn0.33Ni0.33Co0.33O2, spinel LiMn2O4,olivine LiFePO4, and Li1+x(M,Mn)1-xOy, having different or similar lattice structures have been developed. Among these materials, the class of layered Li-rich Mn-transition metal oxides (Li1+x(M,Mn)1-xOy) has lately drawn escalated attention due to their potential high capacities beyond 200 mAh/g. In these oxides, the excess Li ion gives rise to the presence of inter-grown Li2MnO3 slabs within Li(M,Mn)O2 matrix to form a layered “composite” structure. These Li2MnO3 slabs may be transformed to electrochemical active MnO2 layers by removal of Li+ upon charging above 4.5 V (versus Li/Li+) and stabilizing the layered structure under high depth of lithiation/de-lithiation during the charge/discharge cycles. During charge and discharge process, the layered composite suffers from the well known phenomena of potential fade. The potential fade has been attributable to the migration of the transition metal ions, notably manganese and nickel, into the lithium layers, causing slow transformation to a spinel-like domain within the crystal lattice. The fade results in gradual loss in energy capacity of the electrode.In this study, a biwedge octahedron-shaped Li1+x(M,Mn)1-xOy powder has been synthesized via a oxalate-based precipitation process followed by high-temperature calcination. The resulting powder shows a large aspect ratio with a width near 10 μm and a thickness of a couple of μm. The large width allows for high powder tap density, while the small thickness enables fast charging-discharging kinetics. More importantly, in either full-cell or half-cell testing, the resulting oxide electrode showed essentially no potential fade after several hundred cycles. The synthesis process and the material and electrochemical characterization results will be presented. Figure 1

Improved electrochemical performance of Li1.2Ni0.2Mn0.6O2 cathode material with fast ionic conductor Li3VO4 coating

Layered lithium-enriched nickel manganese oxides Li1.2Ni0.2Mn0.6O2 have been synthesized and coated by fast ionic conductor Li3VO4 with varying amounts (1, 3, and 5 wt%) in this paper. The effect of Li3VO4 on the physical and electrochemical properties of Li1.2Ni0.2Mn0.6O2 has been discussed through the characterizations of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), discharge, cyclic performance, rate capability, and electrochemical impedance spectroscopy (EIS). The discharge capacity and coulomb efficiency of Li1.2Ni0.2Mn0.6O2 in the first cycle have been improved after Li3VO4 coating. And, the 3 wt% Li3VO4-coated Li1.2Ni0.2Mn0.6O2 shows the best discharge capacity (246.8 mAh g−1), capacity retention (97.3 % for 50 cycles), and rate capability (90.4 mAh g−1 at 10 C). Electrochemical impedance spectroscopy (EIS) results show that the R ct of Li1.2Ni0.2Mn0.6O2 electrode decreases after Li3VO4 coating, which is due to high lithium ion diffusion coefficient of Li3VO4, is responsible for superior rate capability.

A novel electrolyte additive for improving the interfacial stability of high voltage lithium nickel manganese oxide cathode

In this work, we propose a novel electrolyte additive phenyl trifluoromethyl sulfide (PTS) to improve the interfacial stability of high voltage lithium nickel manganese oxide (LiMn1.5Ni0.5O4) cathode/electrolyte. At 1C rate, addition of 0.5% PTS improves the capacity retention of LiNi0.5Mn1.5O4 from 65% to 84% after 450 cycles at room temperature, and from 64% to 95% after 100 cycles at evaluate temperature. Density functional theory calculation and experimental characterization demonstrate that PTS oxidizes preferentially to the carbonate base electrolyte, generating a SEI film, which effectively suppresses the continuous decomposition of carbonate base electrolyte and the structural destruction of LiMn1.5Ni0.5O4.

Limited nanospace for growth of Ni–Mn composite oxide nanocrystals with enhanced catalytic activity for deep oxidation of benzene

A nanocasting method was applied to synthesize porous manganese oxide, nickel oxide and manganese nickel mixed oxide successfully. The growth of oxide nanocrystals took place in the limited nanospace provided by SBA-15 template and the resulted materials showed a porous structure with high specific surface area. All catalysts were characterized by XRD, SEM, TEM, BET, XPS, H2-TPR techniques and further tested for total oxidation of benzene. The mixed oxide with a higher surface area (162.6m2g−1) exhibited the best activity (T90%=249°C at a high space velocity of 120,000mLg−1h−1), which is much higher than that of the pure oxide. The formation of Mn–Ni solid solution oxide prevented the growth of nanocrystals and the strong synergistic effect gave rise to more adsorbed oxygen species and better low temperature reducibility, which make a great contribution to its superior activity.