Oxygen Desorption Research Articles

Close-Contact Oxygen Vacancies Synthesized by FSP Promote the Supplement of Active Oxygen Species To Improve the Catalytic Combustion Performance of Toluene.

Catalytic combustion is an important means to reduce toluene pollution, and improving the performance of catalytic combustion catalysts is of great significance for practical applications. The study of oxygen vacancies is one of the key steps to improve catalyst performance. Here, two different oxygen vacancy structures were well-defined and controllably synthesized by flame spray pyrolysis (FSP) to evaluate their effect on the catalytic combustion performance of toluene. The closely contacted oxygen vacancies (c-Vo) enhance the oxygen activation capacity of the catalyst, and the temperature of the first oxygen desorption peak and hydrogen reduction peak is 56 and 37 °C lower than the separated oxygen vacancy (s-Vo) sample, respectively. The oxygen activation energy barrier on the c-Vo is calculated to be negligible of only 0.04 eV. Both in situ DRIFT and DFT calculations indicate that the c-Vo structure accelerates the catalytic oxidation of p-toluene molecules. Moreover, due to the unique characteristics of high-temperature synthesis and rapid quenching, FSP brings excellent water resistance and high-temperature stability to the catalyst. In conclusion, utilizing the FSP in situ reduction strategy can create more c-Vo to improve the catalytic combustion performance of toluene.

Effect of yttrium and manganese addition on catalytic soot combustion activity and anti-high-temperature stability of CeO2 catalyst

In order to analyze the influence of the addition of yttrium and manganese on the soot combustion performance and high temperature stability of CeO2 catalyst, a series of Y/Mn-modified CeO2 catalysts were prepared. The effects of structural properties, textural properties, oxygen vacancies, Ce3+, surface adsorbed oxygen species, reduction properties and desorption properties of oxygen species on the activity were analyzed by various characterization methods. The results of the activity test show that the addition of manganese is beneficial to enhancement of the activity, while the addition of yttrium increases the amount of reactive oxygen species, but decreases the activity. After aging at 700 °C, the activity of the CeMn catalyst decreases most sharply, while the catalytic activity of the CeY catalyst can be maintained to a certain extent. Interestingly, the addition of yttrium and manganese at the same time can stabilize the activity. The fundamental reason is that yttrium and manganese move to the surface of the solid solution after aging, which increases the reduction performance of the catalyst, thus contributing to the increase of activity. Although the activity of CeYMn catalyst decreases after aging at 800 °C, it is still higher than that of other catalysts aged at 700 °C.

Oxygen Desorption by Graphene-Based Carbon Films Obtained Through Sublimation

Background: Nanocarbon materials are known as highly sensitive gas sensors when compared to common solid-state sensors. This manuscript discusses graphene-based carbon films as materials for a gas sensor operating at near room temperature. Methods: The structural characteristics of graphene-based carbon films on In2O3- and ITO- coated substrates were studied by confocal laser microscopy, SEM, and Raman spectroscopy. Microwave conductivity was measured by using a λ/4 coaxial resonator based on a symmetric two-wire line in the frequency range 0.65 - 1.2 GHz and the temperature range 290-360 K. Results: The results obtained showed that films on In2O3 - and ITO-coated substrates desorb oxygen from the various structural levels of graphene-based carbon, such as crystalline contacts between globular nanoparticles and distorted graphene fragments. A correlation between the size of nanoparticles in films and the desorption temperature was also revealed. Conclusion: Our studies have shown that thin films of natural graphene-based carbon are promising as gas sensors. The possibility of varying characteristic oxygen desorption temperatures on different substrates is discussed.

Reversible c(4x4)↔(1x2) phase transition on the Ba/Ge(100) surface controlled by oxygen adsorption and desorption

Reversible c(4x4)↔(1x2) phase transition on the Ba/Ge(100) surface controlled by oxygen adsorption and desorption

Origin of enhanced conductivity in low dose ion irradiated oxides

Significant resistivity variations have previously been observed in oxides subjected to relatively low ion irradiation doses, nominally insufficient to generate the amount of bulk defects needed to explain the phenomena. In an effort to unveil the underlying mechanisms, we performed a systematic comparative study of the resistivity evolution in In2O3-based oxides as a function of low ion doses and ultraviolet (UV) illumination, observing striking correlations. Specifically, we found that irradiation with ∼3 × 1012 Si/cm2 and ∼18 h UV exposure result in similar resistivity drops, interpreted in terms of irradiation/illumination assisted desorption of oxygen containing species from the surface. This was further proven by post-irradiation exposure of one of the samples to an oxygen atmosphere partially restoring the resistivity. Combining the present results with literature data, we conclude that the radiation tolerance of In2O3-based and similar oxides depends on the surface charge modifications, individual defect contributions, and contributions from defect complexes at low, intermediate, and high doses, respectively.

Catalytic Behavior of Ag-Mn Catalyst for Efficient Toluene Removal at Low Temperature: Effect of Redox Property

Ag-Mn bimetallic catalysts were prepared by liquid-phase redox method and discussed their synergistic effect on the catalytic oxidation of toluene. The activity order of the catalysts was: Ag-Mn > Mn > Ag-Mn-R > Mn-R. The addition of Ag caused some K+ to be substituted over Ag-Mn, which resulted in the collapse of the structure, and led to more lattice defects and increased the active species. Furthermore, the Ag-Mn catalyst contained a large amount of Mn4+ and Olatt species, the best low-temperature reducibility and the lowest oxygen desorption temperature. After the reduction treatment, the high-valent manganese ions decreased, and the lattice oxygen concentration was greatly reduced. Besides, the high concentration of high valence manganese, easily released lattice oxygen and oxidized silver of Ag-Mn could contribute to the superior catalytic performance. The mechanism followed by toluene → benzoate → benzoquinone → manganese carbonate → CO2 + H2O.

Synthesis and characterization of molybdenum trioxide with an orthorhombic crystal structure for supercritical water gasification application

Supercritical water (SCW) catalytic gasification is promising for the production of synthetic gas from biomass. However, maintaining the activity of heterogeneous catalysts under high pressure and hydrothermal conditions is the most important. Therefore, this study investigates the activity and stability of molybdenum trioxide (MoO3) for the gasification of formaldehyde in SCW. MoO3 with an orthorhombic crystal structure was synthesized by the sol-gel method and tested in the gasification of formaldehyde in SCW. Structural and morphological changes of MoO3 with supercritical water gasification were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), a scanning electron microscope (SEM), N2 adsorption-desorption, thermogravimetric analysis (TGA), temperature-programmed desorption of oxygen (O2-TPD), temperature-programmed desorption with ammonia (TPD-NH3), and temperature-programmed reaction of hydrogen (H2-TPR). The XRD results show that MoO3 has an orthorhombic crystal structure. Its structure changed to a monoclinic structure upon gasification with supercritical water. SEM images showed that the rod-shaped catalyst particles transformed into thin planar plates at high pressure and temperature conditions in the presence of carbonaceous compounds. H2-TPR and XRD results showed that MoO3 was reduced to MoO2 during SCW gasification with hydrogen and carbonaceous compounds. Moreover, the oxygen stability of the catalyst changed during SCW gasification, and active oxygen species formed on the surface of the catalyst. Compared with homogeneous gasification, in the presence of the MoO3 catalyst, the fractions of CO2 and CH4 increased to 50% and 8.4%, respectively, and the fractions of H2 and CO decreased from 37.8% and 11.8% to 32.2% and 3.9%, respectively, due to the changed decomposition mechanism. Orthorhombic molybdenum oxide can be proposed as a promising catalyst for methane production.

B, N co-doping graphene nanoribbons as effective oxygen reduction electrocatalyst

In this study, a facile method was used to synthesize B, N-co-doped graphene nanoribbons (BN-GNRs), with g-C3N4 as a source of N and boric acid as a source of B, for use as an effective electrocatalyst for the oxygen reduction reaction (ORR). Numerous wavy edges are exposed in GNRs, and these exposed wavy edges provide doping positions for N and B atoms. Compared with single doping of B or N, co-doping of B and N with opposite electronegativity can increase the doping amounts. Thus, the obtained BN-GNRs catalyst has tremendous graphitic- and pyridinic-N active sites, which are beneficial to oxygen adsorption and desorption and to electron mass transfer. Additionally, the interaction between nearby N and B can promote the ORR’s catalytic process and conversion efficiency. BN-GNRs demonstrate strong ORR performance, better selectivity, and stability. Moreover, their half-wave potential can reach 0.852 V in alkaline electrolyte, similar to that for Pt/C. This study shows that BN-GNRs can be employed as an effective metal-free ORR catalyst to replace commercial Pt/C.

Kinetics of oxygen sorption-desorption processes in manganites of La0.7Sr0.3Mn0.9Fe0.1O3-δ composition

Based on the data of thermogravimetric analysis the values of the oxygen index (3-δ) in the manganite of the La0.7Sr0.3Mn0.9Fe0.1O3-δ composition, obtained by solid-phase reaction technique, have been calculated. The analysis of oxygen sorption-desorption curves showed that the processes of oxygen release and absorption at pO2 = 10 Pa and pO2 = 400 Pa are not reversible. The minima of the derivative dδ/dt = f (T) corresponding to the maxima of the oxygen extraction rate indicate the complex character of changes in the oxygen desorption rate from manganite. The decrease in the heating and cooling rate from 6.6 K/min to 2.6 K/min resulted in a significant change in the value ∆δ, indicating the dependence of anion mobility on the oxygen concentration in the magnet structure. It has been revealed that in the La0.7Sr0.3Mn0.9Fe0.1O3-δ manganite the oxygen desorption kinetics is well described by the exponential dependence on the Kramers model, which implies no return of desorbed oxygen to the sample. This model indicates the non-stationarity of the diffusion flux through the barrier during desorption of oxygen from samples. The calculation of the activation energy of oxygen desorption by the Merzhanov method at various partial pressures of oxygen has shown that at the initial stage of oxygen extraction from La0.7Sr0.3Mn0.9Fe0.1O3-δ, the activation energy of oxygen desorption has a minimum value (Еа = 103.7 kJ/mol at δ = 0.005) and as the concentration of oxygen vacancies increases, it rises reaching saturation (Еа = 134.3 kJ/mol at δ = 0.06). It is assumed that with an increase in the concentration of oxygen vacancies, an interaction occurs between them, followed by the processes of their ordering with the formation of associates.

First-principles investigation of CuO decomposition and its transformation into Cu2O

This paper reports on the mechanisms of CuO decomposition and its associated phase transformation into ${\mathrm{Cu}}_{2}\mathrm{O}$, as a fundamental step of thermite materials reaction, where CuO serves as the oxidizer. The Frenkel pair defects in perfect bulk CuO show extremely high formation energy (>4 eV) indicating that its decomposition initiates at defects/interfaces/surfaces, the latter being sensitive to surface orientation. In contrast to a variety of CuO surfaces [(111), (110), ($10\overline{1}$)] exhibiting three-fold coordinated oxygen atoms, results show that oxygen vacancy formation requires higher disordered surfaces, such as the CuO(001), on which the vacancy formation activation energy is reduced to 1.31 eV. This leads to the exothermic formation of a chemisorbed O-O peroxy-bridge complex at the surface (\ensuremath{-}1.25 eV adsorption) that thermodynamically moderates the backreaction (vacancy annihilation). Further desorption of molecular oxygen necessitates an activation of 1.53 eV, compatible with CuO decomposition observed experimentally at 600 K (\ensuremath{\sim}second process duration). As a driving mechanism of oxygen release upon decomposition, migrations of the vacancy close to the surface and towards the bulk are determined for a number of crystalline directions and surface orientations and show considerable anisotropy, with two preferential directions: [110] and [001] with 1.35 and 1.77 eV activation, lowered to 1.08 and 1.03 eV activation when approaching the (111) and (001) surfaces, respectively. Finally, the CuO to ${\mathrm{Cu}}_{2}\mathrm{O}$ phase transformation follows a two-step process: a first structural modification from monoclinic to orthorhombic takes place when CuO has lost 12.5% of its oxygen atoms, followed by a barrierless transition to the cubic phase when 44--48% of the oxygen atoms have been removed, i.e., very close to stoichiometric ${\mathrm{Cu}}_{2}\mathrm{O}$.

Designing one-step co-assembled Pr1.95Ce0.05CuO4-Ce0.8Pr0.2O1.9 composite cathode with extraordinary oxygen reduction activity for solid oxide fuel cells

There remains a major challenge to develop highly active oxygen electrode for solid oxide fuel cells (SOFCs). Herein, we report a one-step co-assembly route for preparing Pr1.95Ce0.05CuO4-Ce0.8Pr0.2O1.9 (PCC-CPO) composite cathode for SOFCs, with a focus on its phase structure, oxygen desorption behavior, electrochemical performance, and oxygen reduction reaction (ORR) process. The PCC-CPO catalyst demonstrates satisfactory ORR activity, as evidenced by a low polarization resistance of 0.04 Ω cm2 at 700 °C. The high peak power density (1.04 W cm−2) is achieved in a single cell with the PCC-CPO cathode. Furthermore, the oxygen reaction kinetic was probed by electrochemical impedance spectroscopy (EIS) and distribution of relaxation time (DRT) analysis. The oxygen adsorption-dissociation process is determined to be the rate-limiting step at the electrode interface. This work highlights an effective strategy for rationally designing composite cathode with superior ORR activity and exceptional stability.

BaCoO3−δ perovskite-type oxygen carrier for chemical looping air separation, part Ⅰ: Determination of oxygen non-stoichiometry and cyclic stability of oxygen carrier

Chemical looping air separation (CLAS) is a cost-effective high-temperature air separation technology, and finding suitable oxygen carriers with high oxygen selectivity and capacity is of vital importance to it. Perovskite-type oxides have been extensively studied as oxygen carriers due to their high oxygen selectivity. In this work, BaCoO3-δ perovskite oxide with large oxygen capacity was proposed as an excellent oxygen carrier for CLAS. BaCoO3-δ perovskite powder was synthesized through a sol–gel method, and the determination of oxygen non-stoichiometry and cyclic stability of BaCoO3-δ was investigated via thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). Results indicated that the oxygen non-stoichiometry of BaCoO3-δ was a function of temperature and oxygen partial pressure, and the empirical formula was determined by linear fitting in the range of δ less than 0.5. The standard enthalpy change and standard entropy change of the oxygen desorption reaction were 169.43 kJ/mol and 156.19 kJ/(mol·K) at δ of 0.38, which increased to 292.58 kJ/mol and 298.81 kJ/(mol·K) at δ of 0.47, respectively. The oxygen desorption amount and desorption rate of BaCoO3-δ remained extremely stable during 50 cycles at 875℃, with an oxygen capacity of approximately 0.018 g O2/g BaCoO3 of each cycle. The kinetics of the oxygen desorption process of BaCoO3-δ perovskite was described using the 3-D diffusion Jander model, and the obtained values of apparent activation energy (Ea) and pre-exponential factor (A) were 209.79 kJ/mol and 1.93E06, respectively. Further results indicated that BaCoO3-δ demonstrated a hexagonal perovskite phase, the desorbed oxygen was provided by lattice oxygen in perovskite, the crystal structure remained stable during cycles, and the micro-morphology slightly changed after 50 cycles.

Layered barium cobaltite structure materials containing perovskite and CdI2-based layers for reversible solid oxide cells with exceptionally high performance

To improve the sluggish kinetics of oxygen electrode reactions in reversible solid oxide cells (RSOCs), a novel layered structure Nd0.1Ca0.1Ba1.8Co9O14 (NCBCO) having alternating perovskite and CdI2-based layers is introduced in this field for the first time as a highly active and durable catalyst. Maximum power densities of NCBCO with zirconia-based cells are high, reaching 2.6 W·cm−2 at 800 °C in solid oxide fuel cell (SOFC) mode. Under a solid oxide electrolysis cell (SOEC) mode, the zirconia-based cell with NCBCO achieves an outstanding current density of − 4.36 A·cm−2 at 800 °C with an applied voltage of 1.6 V, surpassing many results of the reported oxygen evolution reaction catalysts with the high activities. Furthermore, RSOCs with NCBCO presents no degradation over entire 400 h in SOFC and SOEC modes. Such outstanding electrocatalytic performances of NCBCO for oxygen electrode reactions might be attributed to its high oxygen vacancy content with a high electrical conductivity. This is confirmed by X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed desorption of oxygen, and electron paramagnetic resonance measurements. These results validate that the layered structure NCBCO can be a potential oxygen electrode material for RSOCs.

Preparation of ultrahigh surface area carbon microspheres under solvent-free hypersaline environment for zinc-air batteries with high power density

It is of great significance to develop efficient non-noble metal electrocatalysts for oxygen reduction reaction (ORR). Herein, the starch-based carbon microspheres (CMS) electrocatalyst with ultrahigh specific surface area (SSA) of 2799 m2 g-1 is prepared by solvent-free method under hypersaline environment that composed of ZnCl2 and FeCl3·H2O. The formed carbon microspheres with hierarchical porous structure are beneficial to the adequate exposure of active sites and the free transportation of electrolyte. Importantly, the hypersaline environment favors not only the high yield of carbon material, but also the creation of abundant carbon defects with the presence of ZnFe2O4 coated on carbon microspheres, thus promoting the oxygen adsorption and desorption. The assembled zinc-air battery based on CMS2-800 exhibits prominent cycle stability, high open circuit voltage (1.43 V) and big power density (183.5 mW cm-2), superior to the battery constructed with commercialized Pt/C + RuO2. This work provides an efficient strategy to prepare electrocatalysts with starch as the starting material for high-performance zinc-air battery.

Liquid-phase mass-transfer processes in packings with a segregated flow model

Liquid back mixing behavior has significant influences on the liquid-side mass-transfer coefficient in packed columns and rotating packed beds(RPBs). And the liquid-side mass-transfer coefficient without the liquid back mixing behavior is called a liquid-side intrinsic mass-transfer coefficient. A ratio of the liquid-side mass-transfer coefficient to the liquid-side intrinsic mass-transfer coefficient is defined as a liquid-side mass-transfer coefficient factor. The lower coefficient factor means the bigger reduction in the liquid-side mass-transfer coefficient. A segregated flow model in packings is developed. From the model, the liquid back mixing effect is first separated from the liquid-side mass-transfer coefficient and is then involved in the coefficient factor, and equations of the liquid-side intrinsic mass-transfer coefficient and coefficient factor are derived. Values of the liquid-side intrinsic mass-transfer coefficient and coefficient factor of oxygen desorption from water in Flexipac 2 structure packing in a packed column were calculated. The values of the intrinsic mass-transfer coefficient were in good agreement of a deviation of 0.58 % with the predictions by theoretical mass-transfer model. Values of the coefficient factor of oxygen desorption from water in a RPB with wire mesh packing were also obtained. Values of the coefficient factor in the RPB rotor were much lower than those in the packed column due to a highly intensified mass-transfer and a higher liquid back mixing in the RPB rotor as compared with those in the packed column. The best method to increase the coefficient factor is to reduce the liquid back mixing and to increase the liquid flow rates in packed columns and RPBs.

Synthesis and properties of polycharge phases in the system La-Li-M-Co-O (M=Ca, Sr, Ba)

Samples of La1-3xLixM2xCoO3-δ (M = Ca, Sr, Ba; 0≤x≤0,1) were synthesized by co-precipitation method. It is shown that the region of their homogeneity lies in the range of substitutions 0≤ x ≤0.05. The volume of the unit cell increases with the size of the alkaline earth metal that replaces lanthanum. Surface morphology of the obtained mixed oxides was studied by SEM. In all samples (except strontium - containing) paramagnetic Co2+ ions from the impurity Co3O4, which are in different local environments and have different degrees of exchange interaction with each other, are contained in the form of chain fragments -Co2+-O2--Co2+-O2--Co2+-O2— and contain defective centers Со2+, which are formed during the desorption of lattice oxygen from the surface, or in the process of diffusion of oxygen from the volume of material to the surface. In strontium-containing samples La0,85Lix0,05Sr0,01CoO3-δ there are mainly ferromagnetic clusters Co3+-Co4+.

Controllable Inverse Photoconductance in Semiconducting Nanowire Films.

As a typical p-type semiconductor, tellurium (Te) has been widely studied for the construction of photodetectors. However, only the positive photoconductance of Te-based photodetectors based on the photoconductive effect has been observed in the reported literature. Herein, an unusual but interesting phenomenon, inthat tellurium nanowires (NWs) behave withnegative photoresponse to positive photoresponse under enlarged optical intensities from the UV to VIS-IR region is reported. According to the experiments and simulations, adsorbed oxygen on the surface of Te NWs plays a significant role in the abnormal photoresponse. The inverse photoconductance can be attributed to the competition between the photoconductive effect and the oxygen desorption effect. Moreover, the influence of the size and layers of Te NWs is also discussed. This inverse photoconductance phenomenon is further explored by introducing the Te-Au heterojunction system. Hot-electron injection at the Te-Au heterojunction interface induces a more obvious tendency to behave with a negative photoresponse. These findings will be beneficial for potential applications of Te-NW-based photodetectors.

Novel first-principles insights into graphene fluorination

Fluorination of graphene sheets with xenon difluoride leads to the formation of the widest bandgap Gr derivative, namely, fluorographene. Accurate experimental observations distinguish two stages of mechanism in the fluorination procedure: the half-fluorination stage, wherein one side of the Gr sheet is rapidly fluorinated, and the full-fluorination stage, involving much slower fluorination of the opposite side of the sheet [R. J. Kashtiban et al., Nat. Commun. 5, 5902 (2014)]. Here, we perform comprehensive density functional calculations to illustrate accurate microscopic insights into the much slower rate of the full-fluorination stage compared with the half-fluorination one. The calculated minimum energy paths for the half- and full-fluorination processes demonstrate much enhanced fluorine adsorption after the half-fluorination stage, which sounds inconsistent with the experimental picture. This ambiguity is explained in terms of significant chemical activation of the graphene sheet after half-fluorination, which remarkably facilitates the formation of chemical contaminants in the system and, thus, substantially slows down the full-fluorination procedure. After considering the binding energy and durability of the relevant chemical species, including hydrogen, oxygen, and nitrogen molecules and xenon atom, it is argued that oxygen-fluorine ligands are the most likely chemical contaminants opposing the complete fluorination of a graphene sheet. Then, we propose an oxygen desorption mechanism to carefully explain the much enhanced rate of the full-fluorination procedure at elevated temperatures. The potential photocatalytic application of the pristine and defected samples in water splitting and carbon dioxide reduction reactions is also discussed.

Influence of the Thermal Processing and Doping on LaMnO3 and La0.8A0.2MnO3 (A = Ca, Sr, Ba) Perovskites Prepared by Auto-Combustion for Removal of VOCs

Single-phase oxygen stoichiometric LaMnO3 and doped La0.8A0.2MnO3 (A = Ca, Sr, Ba) perovskites have been prepared by a simple one-step auto-combustion method. Cation-deficient LaMnO3+δ and La0.8A0.2MnO3+δ were obtained by calcination of the former samples in air at 750 °C. The samples were characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction, temperature-programmed oxygen desorption, and N2 physisorption in order to apply them as catalysts in the complete catalytic oxidation of acetone as a model volatile organic compound. The studied phases show the expected orthorhombic and rhombohedral perovskite crystal structures. Catalytic experiments performed with all the samples show measurable activity already at 100 °C. At 200 °C, doped La0.8A0.2MnO3 samples show higher activity than undoped LaMnO3, with increasing conversion with larger A-cation size. Calcined samples also show higher activity than as-prepared ones making La0.8Ba0.2MnO3+δ the best catalyst at this temperature. All doped samples show >95% acetone conversion at T ≥ 250 °C with a weak dependence on the sample processing or A cation doping. The collected evidence confirms that the most important factors for the catalytic activity of these oxides are the Mn4+/Mn3+ molar ratio on the surface of the samples and the cation-deficiency of the bulk perovskite structure. In addition, increasing the symmetry of the bulk crystal structure appears to have an additional favourable effect. Despite the observation of the presence of surface carbonates, we show that it is possible to use the as-prepared samples without further thermal treatment with good results in the oxidation of acetone.

Analytical transmission electron microscopy investigation of electrochemically Li+–Na+ substituted LiNi0.5Mn1.5O4 electrode

The electrochemical Li+–Na+ alkaline cation substitution of a lithium nickel manganese oxide (LiNi0.5Mn1.5O4, LNMO), which is characterized via structural analysis, has previously been reported. However, detail characterizations of the chemical and electronic features are lacking. In this study, we characterized that by using analytical transmission electron microscopy. Energy dispersive X-ray spectroscopy (EDS) revealed uniform Na-insertion into a single particle. Electron energy-loss spectroscopy (EELS) analysis exhibited complete Li-extraction. Energy loss near edge structure (ELNES) of Mn and Ni L-edges indicated that only Ni contributes to the redox reaction as Ni2+ ​⇔ ​Ni4+ during the Li+–Na ​+ ​substitution. The elemental composition ratio analysis using both EDS and EELS indicated Na0.6Ni0.5Mn1.5O3.8 as a formula of the Na-substituted material. Oxygen desorption was provoked during the Na-insertion process, and oxygen defect formation was found to be essential for the Li+–Na+ substitution mechanism of the LNMO material.