Mn Co-doping Research Articles

Mn and Ti Co-doping of LiNiO2 to Improve Performance

LiNiO2 (LNO) has high capacity but suffers from structural instability and capacity fade, which limits its practical use in lithium-ion batteries. This study proposes co-doping LNO with Mn and Ti (MnTi25) as a strategy to overcome these issues. MnTi25 was thoroughly characterized, revealing improved structural stability and significantly reduced cation mixing compared to pristine LNO. The half-cell performance of MnTi25 is noteworthy, exhibiting a capacity similar to the established 4% Mn-substituted ZoomWeMn4 standard, demonstrating efficient Li-ion extraction and insertion. Additionally, full-cell testing against a graphite anode shows that MnTi25 delivers a capacity almost identical to a commercial LNO-based material. This promising achievement highlights the effectiveness of co-doping in addressing LNO's limitations while preserving its high-capacity potential. This study demonstrates that MnTi25 can be a promising cathode material for high-performance lithium-ion batteries by tailoring the material's structure through co-doping.

Novel Co and Cr free, high-temperature black ceramic pigment based on (Ni, Mn) co-doping (CuFe)Fe4O8

Novel Co and Cr free, high-temperature (Ni, Mn) co-doping (CuFe)Fe4O8 black ceramic pigment was synthesized. The results indicate that the brightness (L*) values of the synthesized pigments decrease first, then reach an optimal value, and then increase with the doping amounts increasing of both Ni2O3 and MnO2. The optimized Ni2O3 and MnO2 doping amounts are 0.20 (molar ratio to (CuFe)Fe4O8) and 0.75 (molar ratio to (CuFe)Fe4O8), respectively. L*, a* and b* values of the optimized pigment (0.20Ni, 0.75Mn) co-doping (CuFe)Fe4O8 are 21.36, 1.10 and −0.24, respectively. The crystal phase of the optimized pigment is (CuFe)Fe4O8 (JCPDS73–2314). The crystal size of the pigment is 0.8–1.5μm with excellent dispersivity. The glazing temperatures have little effect on the coloration of the pigment when used at 1000℃, 1150℃ and 1300℃. The results show that the pigments have excellent high-temperature resistance and are expected to be widely used in high-temperature glazing coloration.

Study on the Influence of Mn and Cl Co-Doping on the Electrochemical and Mechanical Properties of LiFePO4: A First-Principles Investigation

Study on the Influence of Mn and Cl Co-Doping on the Electrochemical and Mechanical Properties of LiFePO4: A First-Principles Investigation

Sr and Mn co-doping PrBaFe2O5+δ optimizes the electrochemical performance and stability of solid oxide fuel cell cathode

Developing cobalt-free cathode with high stability and high electrochemical activity is very important for constructing low-cost, high-performance solid oxide fuel cells. Layered perovskite PrBaFe2O5+δ (PBF) is known to ave important magnetic, oxygen exchange kinetic and electrochemical properties. In this study, Sr and Mn co-doping A-site and B-site of PrBa0.5Sr0.5Fe1.6Mn0.4O5+δ (PBSFM) electrode was synthesized and characterized its properties. The first-principles calculation shows that Sr and Mn co-doped PBSFM decreases the oxygen vacancy energy, improves the overlap of oxygen-metal bond hybridization and structural stability. The polarization resistance (Rp) of PBSFM decreases from 0.22 to 0.077 Ω cm2 at 700 °C. At 800 °C, the power density of fuel cell reaches 674 mW cm−2 using hydrogen as fuel. In addition, Sr and Mn co-doped PBSFM significantly improves impedance and single cell stability under operating conditions.

Narrowing Band Gap of Zno Codoping (Al+Mn) as a Photocatalyst Candidate for Degraded Textile Dye Wastewater

Photocatalyst degradation is one method to reduce industrial textile dye pollution in water. In this study, ZnO material has been synthesized by codoping Al and Mn by chemical coprecipitation method to determine the structural properties and optical properties of the material. From this research, it was found that the structure of ZnO after codoping Al and Mn did not change the hexagonal wurtzite phase but changes in other lattice parameters. The addition of Mn and Al codoping is reported to affect the intensity of XRD peaks, especially on the 101 lattice. The higher the scattering peak, the more angular the shift, indicating the magnitude of oxygen vacancies. The reflectance confirms this result that increasing Mn concentration decreases the energy gap to 3.258 eV. From these structural properties and energy gap values, ZnO codoping Al and Mn materials can be included in candidate materials that can be used as photodegradation agents for textile dyes.

Synergistic N/Mn Codoping Deagglomerate Carbon Coating of LiFePO4/C To Boost Electrochemical Performance.

LiFePO4 is widely used because of its high safety and cycle stability, but its inefficient electronic conductivity combined with sluggish Li+ diffusivity restricts its performance. To overcome this obstacle, applying a layer of conductive carbon onto the surface of LiFePO4 has the greatest improvement in electronic conductivity and Li+ diffusivity. However, the rate performance of carbon-coated LiFePO4 makes it difficult to meet the application requirements. Although nitrogen doping improves electrochemical performance by providing active sites and electronic conductivity, the N-doped carbon coating is prone to agglomeration, which causes a sharp decrease in capacity when the current rate increases. In this work, a synergistic N, Mn codoping strategy is implemented to overcome the aforementioned drawbacks by disrupting the large agglomeration of C-N bonds, improving the uniformity of the surface coating layer to enhance the completeness of the conductive network and increasing the number of Li+ diffusion channels, and thus accelerating the mass transfer rate under high-rate current. Consequently, this strategy effectively improves the rate capability (119 mA h g-1 at 10 C) while maintaining excellent cycling performance (88% capacity retention over 600 cycles at 5 C). This work improves the rate of ion diffusion and the rate capability of micrometer-sized LiFePO4, thus, enabling its wider application.

Effect of Eu and Mn co-doping on temperature dependent dielectric relaxation behaviour and electric conduction mechanisms of bismuth ferrite

Effect of Eu and Mn co-doping on temperature dependent dielectric relaxation behaviour and electric conduction mechanisms of bismuth ferrite

Fabrication of Ni and Mn co-doped ZnFe2O4 spinel ferrites and their nanocomposites with rGO as an efficient photocatalyst for the remediation of organic dyes

Herein, we have synthesized Ni and Mn co-doped ZnFe2O4 ferrites using the simple co-precipitation method and their nanocomposites (NCs) with 10 % rGO using the ultra-sonication route. The structural investigation revealed the successful formation of single-phase ZnFe2O4 NPs with cubic spinel ferrite geometry. The crystallite size was determined to be in the range of 21 nm to 28 nm. The current–voltage (I-V) analysis revealed that Ni and Mn co-doping and the addition of rGO nanosheets in ZnFe2O4 NPs boosted the electrical responses of the fabricated Zn1-xNixFe2-yMnyO4/rGO NCs. The BET analysis indicates an increase in the surface area of Zn1-xNixFe2-yMnyO4/rGO NCs (132 m2/g) that might be attributed to the inclusion of rGO nanosheets, which prevents the NPs from agglomeration. The photocatalytic evaluation of the pristine ZnFe2O4 NPs, Ni and Mn co-doped Zn1-xNixFe2-yMnyO4 NPs, and Zn1-xNixFe2-yMnyO4/rGO NCs photocatalysts was tested by photodegradation of malachite green (MG) dye under sunlight irradiation. Results exhibited improved photocatalytic responses and degraded 94.6 % of MG dye in 45 min using Zn1-xNixFe2-yMnyO4/rGO NCs, which was much higher compared to the Ni and Mn co-doped Zn1-xNixFe2-yMnyO4 NPs (58.7 %) and pristine ZnFe2O4 NPs (38.3 %). The increased degradation potential of Zn1-xNixFe2-yMnyO4/rGO NCs was accredited to the highly conducting nature and 2D nano-sheets of rGO, which efficiently inhibited the recombination of charge carrier species. Ultimately, the remarkable photocatalytic capability exhibited by Zn1-xNixFe2-yMnyO4/rGO NCs implies that the synthesized NCs could have auspicious practical applications in the elimination of dyes from wastewater.

Origin of high comprehensive electromechanical properties of novel donor and acceptor–codoped PMN–30PT ceramics

Donor and acceptor–codoped PMN–30PT ceramics with 1–3 mol% Sm and 1 mol% Mn were fabricated via a two-step solid-state reaction. The crystal structure and electrical properties were investigated in detail. Donor Sm and acceptor Mn codoping substantially enhances the electromechanical, piezoelectric, and dielectric properties with a high piezoelectric coefficient d33 = 483–680 pC/N, a high mechanical quality factor Qm = 518–642, a high field-induced strain = 0.20%–0.24 %, and a low dielectric loss tan δ = 0.54%–0.69 %. X-ray diffraction and Raman spectra reveal the coexisting triple phase composition of the rhombohedral phase, tetragonal phase, and monoclinic polar nanoregions. Thermally stimulated depolarization current verifies the formation of various defect dipole clusters such as (MnTi″–VO··)×. With enhanced local structure heterogeneity induced by Sm, the phase composition and defect chemistry are regarded as the origin of such high comprehensive performance.

First-principles prediction of enhanced photocatalytic activity in La-X (X = Sc, V, Cr, Mn, Fe, Co, Ni, or Cu) Co-doped SrTiO3

The influence of La-X (X = Sc, V, Cr, Mn, Fe, Co, Ni, or Cu) co-doping on the electronic structure and photocatalytic activity of SrTiO3 system was investigated using the open-source software package Quantum Espresso (QE) based on density functional theory. Defect formation energy calculations showed an energy advantage for co-doped systems under Ti-poor and O-rich conditions. The La-V, La-Cr, La-Mn, La-Fe, and La-Ni co-doped systems showed magnetic properties with corresponding total magnetization of 0.08 µB, 2.97 µB, 3.30 µB, 1.00 µB and 1.00 µB, respectively. The La-X (X = V, Cr, Mn, Fe, Ni, or Cu) co-doped system exhibits photoabsorption activity in the visible region as compared to the pure SrTiO3. The La-X (X = Cr, Fe, Ni, or Cu) co-doped SrTiO3 exhibits a long carrier lifetime, especially the La-Fe co-doped system with a high effective mass ratio of holes to electrons of 5.79. However, the redox potential of the water decomposition reaction of the La-Cu co-doped system is too large, making it unsuitable for water splitting. In summary, the La-X (X = Cr, Fe, or Ni) co-doped systems exhibited intermediate states in the band structure and density of states, which better meet the specific requirements for photocatalysis compared to systems without intermediate states, showing superior photocatalytic potential. The band edge alignment of the three co-doped systems with water redox potentials demonstrated good matching. These findings suggest that La-X (X = Cr, Fe, or Ni) co-doped SrTiO3 is a promising candidate material for solar-driven water splitting.

Investigation of Mn Single and Co-Doping in Thermoelectric CoSb3-Skutterudite: A Way Toward a Beneficial Composite Effect

Investigation of Mn Single and Co-Doping in Thermoelectric CoSb₃-Skutterudite: A Way Toward a Beneficial Composite Effect

Comprehensively enhanced strain performance in PIN-PMN-PT ferroelectric ceramics via composition and orientation engineering

Excellent overall strain performances (i.e., low hysteresis, giant strain, and wide temperature span) are highly desirable in commercial high-precision displacement actuators to satisfy different application scenarios. However, any single means, e.g., compositional design or orientation engineering can hardly achieve the overall improvement of strain properties in ceramics. In this work, an approach of integrating compositional design (Sm and Mn co-doping) and orientation engineering (<001>-textured) is proposed to enhance the strain performance of 0.27Pb(In1/2Nb1/2)O3-0.40Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 (PIN-PMN-PT) comprehensively. Initially, with the co-doping of Sm and Mn, the hysteresis of PIN-PMN-PT is substantially decreased to approximately 0.43 times that of the undoped material. Subsequently, 5 wt% BaTiO3 (BT) templates were added during the tape-casting process to orient the grains in 1 mol% Sm and Mn-doped PIN-PMN-PT ceramics. This resulted in a unique "4R" domain configuration with a reduced domain size of 0.13 µm. As a result, the domain wall energy was lowered, and the strain strength was increased to 0.35% at 70 kV/cm with low hysteresis to 8.94%. Moreover, the "clamping effect" in textured ceramics generates additional stress due to the lattice mismatch between the matrix grains and the BaTiO3 template, which inhibits the rhombohedral to the tetragonal phase transition. In addition, the fluctuation of strain value was only 8.5% over a wide temperature range of 30–150 °C, demonstrating excellent temperature stability. As a result of the combined effect of ion doping and orientation engineering, the overall strain performance in PIN-PMN-PT has been improved, providing a novel approach to designing superior and practical displacement actuators.

Ferromagnetism in (Cr, Mn)-co-doped 3C–SiC analyzed using density functional theory

In this work, the influence of Cr and Mn impurity atoms on the electronic structure and magnetic properties of 3C–SiC was analyzed by carrying out first-principles calculations using the GGA + U method, and the influence of Si vacancies on the co-doped system was also considered. The results showed 3C–SiC systems mono-doped with Cr and Mn atoms to be spin-polarized had total magnetic moments of 3.05 and 5.00 μB, respectively. The ferromagnetic state of each of various (Cr, Mn)-co-doped 3C–SiC systems was determined to be more stable than the antiferromagnetic state, with a magnetization energy of −702.3 meV for the most stable system and a total magnetic moment of about 6.00 μB. Finally, the effect of Si vacancies on the doping system was considered on the basis of (Cr, Mn) co-doping. The introduction of Si vacancies reduced the ferromagnetism of the (Cr, Mn)-co-doped 3C–SiC system. The calculations performed in this research have provided a theoretical basis for using (Cr, Mn)-co-doped 3C–SiC as a spintronic device.

Sn and Mn co-doping synergistically promotes the sensing properties of Co3O4 sensor for high-sensitive CO detection

In the realm of gas sensors, p-type metal oxide semiconductor (MOS) usually exhibits inherently low sensitivity toward target gases caused by the hole accumulation layer configuration, which seriously hinders its practical application. Diatomics co-doping is an efficient tactic for adjusting the characteristics of MOS related to gas-sensing due to their synergistic effect. In this work, we controllably synthesized bare Co3O4, Sn-doped Co3O4, Mn-doped Co3O4 and Sn/Mn co-doped Co3O4 nanosheets. The experimental results reveal that Sn/Mn co-doped Co3O4 sample presents porous nanosheets structure. 1 mol% Sn/Mn co-doped Co3O4 sensor presents enhanced response [(Rg-Ra)/Ra = 330 %∼40 ppm at 150 °C] toward CO compared with the bare Co3O4, 1 mol% Sn-doped Co3O4, and 1 mol% Mn-doped Co3O4 nanosheets. Besides, 1 mol% Sn/Mn co-doped Co3O4 nanosheets show a low limit of detection (500 ppb/experimental value), good stability and selectivity. We infer that the good CO-sensing properties may be ascribed to the oxygen vacancies defects generated by Sn4+ and Mn2+/Mn3+ co-doping, high Co3+ ratio, and high specific surface area. This study affords an effective co-doping strategy for enhancing the gas-sensing performances of p-type MOS.

Effect of Mg and Mn co-doping on the high electrical properties of BiFe1-2xMgxMnxO3−BaTiO3 lead-free ceramics prepared by sol–gel method and two-step sintering method

Effect of Mg and Mn co-doping on the high electrical properties of BiFe1-2xMgxMnxO3−BaTiO3 lead-free ceramics prepared by sol–gel method and two-step sintering method

Improvement of piezoelectric properties of Bi4Ti3O12 ceramics by Mn/Ta co-doping and direct reaction sintering

Bi4Ti3-x (Mn1/3Ta2/3)xO12 piezoelectric ceramics were prepared by conventional sintering and direct-reaction sintering in this study. The effect of B-site Mn/Ta co-substitution and sintering method on the microstructure and electrical properties of Bi4Ti3-x (Mn1/3Ta2/3)xO12 piezoelectric ceramics was systematically investigated. The experimental results show that the combination of high-valent Ta and low-valent Mn ions replacing Ti4+ ions reduce the concentration of oxide vacancy defects in BITMT ceramics. The direct-reaction sintering is a simpler preparation method and the prepared samples have more uniform grain distribution and higher density. The resistivity of the direct reaction sintered sample with x = 0.05 at 500 °C is 7.19 × 105 Ωcm, the residual polarization is 8.1 μC/cm2, and the temperature stability of the piezoelectric constant is good. Therefore, the present study suggests that the piezoelectric properties of Mn and Ta co-doping of BIT ceramics could be greatly enhanced via the direct-reaction sintering, which provides a promising alternative to the conventionally sintered for a more cost-effective preparation for BIT ceramics.

Theoretical study on site preference of Mn in B-containing Ni3Al alloys and elastic properties

γ′-Ni 3 Al is the key strengthening element of nickel-based superalloys. Adding alloying elements can improve elastic properties of Ni 3 Al. Therefore, investigating the occupancy behavior of alloying elements in Ni 3 Al is very important to unravel their influence on the elastic properties of Ni 3 Al. In this work, the first-principles plane wave pseudopotential method combined with Wagner-Schottky model is used to explore the occupancy behavior of Mn in B-doped γ′- Ni 3 Al. It is shown that B always occupies the octahedral interstices of Ni 3 Al regardless of alloy composition and temperature. At 0 K, Mn has no obvious occupancy tendency in pure and B-doped Ni 3 Al. With the increase of temperature, the tendency of Mn occupying the Al sites increases in stoichiometric and Al-rich alloys while it decreases in Ni-rich alloys. B doping can suppress the occupancy reversal of Mn in Ni 3 Al induced by temperature. The analysis of elastic properties reveals that the ductility of alloys can be improved by B or/and Mn co-doping. In particular, synergistic alloying of B and Mn can evidently enhance the ductility of Ni 3 Al alloys. Such synergistic effect demonstrates promising potential applications of Ni-based superalloys in extreme mechanical environments by adjusting alloy composition, temperature and alloying elements.

(Ca,K)(Zn,Mn)2As2: Ferromagnetic semiconductor induced by decoupled charge and spin doping in CaZn2As2

We have successfully synthesized a novel diluted magnetic semiconductor (Ca1−2x K2x )(Zn1− x Mn x )2As2 with decoupled charge and spin doping. The substitutions of (Ca2+, K+) and (Zn2+, Mn2+) in the parent compound CaZn2As2 (space group P m1 (No. 164)) introduce carriers and magnetic moments, respectively. Doping only Mn into CaZn2As2 does not induce any type of long range magnetic ordering. The ferromagnetic ordering arise can only when K+ and Mn2+ are simultaneously doped. The resulted maximum Curie temperature reaches ~7 K, and the corresponding coercive field is ~60 Oe. The transport measurements confirm that samples with K and Mn co-doping still behave like a semiconductor.

Morphology controlled synthesis of Fe and Mn co-doped In2O3 nanocubes and their Dopant-Atom effects on electronic structure and magnetic properties

Fe and Mn co-doped In2O3 single-phase cubic crystal structure nanocubes of uniform size and control over dopant concentration (In1.96Fe0.02Mn0.02O3, In1.94Fe0.02Mn0.04O3, In1.92Fe0.02Mn0.06O3 and In1.90Fe0.02Mn0.08O3) and microstructure were prepared using the hydrothermal-annealing technique. On a wider vision, we systematically investigated the influence of Fe and Mn co-doping in In2O3 through complementary experimental techniques and density functional theoretical (DFT) calculations to reveal the physical mechanisms involved in the origin of observed ferromagnetism. DFT calculations demonstrated that the substitution of surface indium atom by iron (FeIn) leads to impurity states on the top of In2O3 valence band maximum (VBM). Conversely, incorporation of interstitial (Mni) impurities in the host matrix without oxygen vacancies (VO) slightly shifts the top of the valence band and incorporation of interstitial Mn-impurity in the In2O3 (111) surface with oxygen vacancy does not provide noticeable changes in the electronic structure of the defective surface. High-resolution transmission electron microscopy measurements showed the formation of regular nanocubes in shape with 36.9–37.6 nm in average edge length. X-ray photoelectron spectroscopy investigations revealed that valence state of Fe mostly as Fe2+ and Fe3+ and Mn2+ for Mn atom in the In1.96Fe0.02Mn0.02O3, In1.94Fe0.02Mn0.04O3, In1.92Fe0.02Mn0.06O3 and In1.90Fe0.02Mn0.08O3. Magnetic studies exhibited room temperature ferromagnetism (RTFM) in the investigated samples with the high coercivity and saturation magnetization of 145.48 Oe and 0.023 emu/g, respectively for the In1.94Fe0.02Mn0.04O3. The origin of observed RTFM was described based on the bound magnetic polaron (BMP) model mechanism. DFT investigations demonstrated the clusters of impurities (FeIn-nMni) robust magnetic interactions within the cluster and between the clusters. Interestingly, only FeIn-nMni clusters contribute ferromagnetism observed in the investigated co-doped systems. Therefore, increasing the concentration of defects leads to the improvement of ferromagnetism. The comprehensive experimental and DFT investigations present new evidence to the observed ferromagnetism and electronic structure of Fe,Mn co-doped In2O3 nanocubes.

Superlattice-Like Co-Doped Mn Oxide and NiFe Hydroxide Nanosheets toward an Energetic Oxygen Evolution Reaction

Superlattice-Like Co-Doped Mn Oxide and NiFe Hydroxide Nanosheets toward an Energetic Oxygen Evolution Reaction