ACS Applied Energy Materials
·
2021
·
IF 6.024
Kaibin Fang,Qian Xie,Chengyun Wang,Xiulian Qiu,Yali Wang,Wei Yang,Xin-wei Yu
LiNi0.8Co0.15Al0.05O2 (LNCA) cathode materials have an extremely high energy density, which can greatly enhance the driving range of pure electric vehicles if they are used in on-board batteries. However, the development of the LNCA cathode material is restricted by the expensive transition metal cobalt (Co). Therefore, researchers are devoted to finding other metals to replace Co to synthesize nickel (Ni)-rich Co-free materials to reduce the cost. To investigate the feasibility of replacing Co with manganese (Mn) as a transition metal, this paper reports the synthesis and compares the properties of four Ni-rich materials with different Co–Mn contents by gradually adding Mn to LNCA materials and reducing the Co content in equal amounts using an oxalic acid coprecipitation method. The results show that Mn can compensate the effect of Co deficiency to a certain extent; it is feasible to use Mn to completely replace Co in the synthesis of Ni-rich ternary Co-free materials under the premise of sacrificing a certain initial specific capacity. The tetrameric material LiNi0.8Co0.1Mn0.05Al0.05O2 substituted with trace amounts of Mn exhibited the most excellent electrochemical properties among the four synthesized materials. Therefore, to synthesize satisfactory Ni-rich Co-free materials, it is suggested to develop and synthesize quaternary Co-free materials on the basis of LiNi0.8Co0.1Mn0.05Al0.05O2.
研究领域:
材料科学
·
电化学
·
电池技术
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2024
·
IF 5.5
Mohamed M. Abdelaal,Mohammad Alkhedher
The energy storage market necessitates an increase in the specific capacity of battery materials, particularly cathodes, to meet growing demands. Manganese (Mn) substitution of lithium iron phosphate (LFP) cathodes presents a promising avenue, offering high specific capacity and operability at elevated voltages. However, during cycling, the dissolution of Fe/Mn ions into the electrolyte leads to capacity fading. In this study, we enhance the specific capacity of LFP by Mn substitution in the iron position at various ratios (0.1, 0.2, 0.3, and 0.4). LiFe 0.6 Mn 0.4 PO 4 exhibits the highest capacity of 159.1 mAh g -1 at 0.1C with an initial Coulombic efficiency of 97.9 %. This improvement stems from an enhanced lithium diffusion coefficient, increasing from 1.86 × 10 –14 cm 2 s -1 for pristine LFP to 2.46 × 10 –12 cm 2 s -1 for LiFe 0.6 Mn 0.4 PO 4 . However, LiFe 0.6 Mn 0.4 PO 4 demonstrates the poorest capacity retention among the substituted samples, reaching 78.4 % over 100 cycles due to severe Fe/Mn ion dissolution. To address this issue, we coat Mn-substituted LFP with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and lithiated Nafion (LN) polymer, which offer high electronic and lithium-ion conductivity, respectively. This coating layer enhances the capacity retention of LiFe 0.6 Mn 0.4 PO 4 to 90.1 % at 0.2C after 100 cycles, effectively mitigating active material loss during charge-discharge processes. This study demonstrates that PEDOT:PSS-LN can improve the electronic and ionic conductivity of cathode materials and maintain high capacity retention during cycling.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2019
·
IF 10.159
Zhiwei Zhou,Junyou Yang,Qinghui Jiang,Jiwu Xin,Sihui Li,Xiaochun Wang,Xuesong Lin,Ruisi Chen,Abudl Basit,Qi Chen
In this work, a composite product of Mn-substituted SnTe, SnO2 nanoparticles, and MnTe-supersaturated precipitates has been fabricated by a simple in situ reaction between SnTe and MnO2 for the first time. Benefiting from the synergistic effect induced by the product of in situ reaction, a remarkable improvement in the thermoelectric performance has been achieved. On the one hand, Mn substitution in SnTe can effectively modify the band structure and enhance the electrical properties of SnTe; on the other hand, the thermal transport can also be dramatically suppressed by in situ reaction-derived multiscale phonon scattering by point defects, SnO2 nanoparticles, and supersaturated MnTe precipitates. Ultimately, a maximum ZT of ∼1.5 at 873 K has been achieved in the SnTe + 10 mol % MnO2 sample, which increases by 224% in comparison with the pristine SnTe, representing one of the best results ever reported for SnTe-based thermoelectric materials.
研究领域:
材料科学
·
热电学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Peng Liu,Yuxi Liao,Jingjing Li,Longwen Chen,Mingli Fu,Puqiu Wu,Runliang Zhu,Xiaoliang Liang,Tianli Wu,Daiqi Ye
The cobalt oxides and manganese oxides have high-activity potential for catalytic oxidation of volatile organic compounds (VOCs), while the mesoporous hollow morphology is crucial to the mass transfer of reactant and product. Therefore, it is worth investigating the effect of manganese substitution in mesoporous hollow cobalt oxides on catalytic oxidation. Herein, a partially disordered spinel structure is formed by the Mn substitution in Co 3 O 4 and the mesoporous hollow microsphere is improved in morphology homogeneity with the decrease of Co/Mn ratio in the range of 1.8–28.8. The 5Co1Mn (Mn-substituted Co 3 O 4 with Co/Mn at 5.4) exhibits outstanding catalytic activity for toluene oxidation with 50% CO 2 generation at 237 °C, which is 21 °C lower than Co 3 O 4 . Moreover, the 5Co1Mn displays satisfactory stability in reusability, lifetime, and water resistance. The small defective crystallite , mesoporous hollow morphology, and high specific surface area endow Mn-substituted Co 3 O 4 with more surface chemical adsorbed oxygen, enhancing the catalytic oxidation of toluene. Theoretical calculation on (3 1 1) plane of Co 3 O 4 reveals that Mn 2+ or Mn 3+ substitution increases the formation energy of oxygen vacancy and makes it difficult to adsorb gaseous oxygen on the defective surface. The interaction between Co and Mn impedes the improvement of toluene oxidation because the mobility of lattice oxygen, the surface distribution of Co 3+ , and the ratio of surface adsorbed oxygen to surface lattice oxygen are hindered by Mn substitution. The chemical adsorbed oxygen is more active than lattice oxygen in the oxidation of adsorbed intermediates (phenolate, benzoate species, etc.). The Langmuir-Hinshelwood mechanism dominates in the catalytic oxidation at 200–250 °C, while the catalytic oxidation follows both the Langmuir-Hinshelwood mechanism and Mars-van Krevelen mechanism above 250 °C. This work provides some enlightenment for exploring the role of surface oxygen species in VOCs oxidation and uncovering the interaction in binary spinel oxides.
研究领域:
催化化学
·
环境科学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yuhang Xin,Qianchen Wang,Yingshuai Wang,Meng Wang,Feng Wu,Hongcai Gao
As an inexpensive and environmentally-friendly cathode for sodium-ion batteries, Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 (NFPP) is considered to be a promising candidate for practical applications. However, the theoretical capacity of NFPP is limited to 129 mAh g −1 , due to the fact that only three electrons can be participated in the reaction during the charge/discharge process. Herein, the critical role of cobalt and manganese in elevating the energy density of the pristine NFPP structure was investigated, and Na 4 Co 0.5 Mn 0.5 Fe 2 (PO 4 ) 2 P 2 O 7 (NCMFPP) is prepared in order to trigger a redox reaction with 3.5 electrons during the charge/discharge process. It is found that the NCMFPP can provide a high initial discharge capacity of 139 mAh g −1 at 0.1C (1C = 129 mA g −1 ), with an excellent rate capacity (75 mAh g −1 at 10C) and a remarkable long cycling stability with a capacity retention of 65.2 % after 2000 cycles at 10C. The reaction of the Mn 3+ /Mn 4+ redox couple was characterized by X-ray photoelectron spectroscopy analysis during the charge/discharge process. These results verified the effectiveness of cobalt and manganese in elevating the energy density of NFPP as a cathode as a cathode material for low-cost sodium-ion batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
·
2023
·
IF 2.7
Feng Tian,Yu Gao,Anping Wang,Lan Xiang,Qikui Man,Hui Xu,Baogen Shen
Efficient microwave absorbing materials are required to solve electromagnetic interference and electromagnetic pollution problems. It has been known that the electromagnetic wave (EMW) absorption properties of ferrites can be improved by element substitution. In this study, the hexagonal Ba 2 Co 2 Mn x Fe 12- x O 22 ( x = 0.0, 0.4, 0.8, 1.2 and 1.6) ferrites were prepared by the solid-phase sintering method, and the effect of Mn substitution on structural, magnetic and microwave absorption performance were investigated in detail. Due to the impact of lattice distortion caused by doping Mn ions in Ba 2 Co 2 Fe 12 O 22 ferrites, the concentration of oxygen vacancy increases first and then decreases with increasing Mn substitution. The real part of complex dielectric constant ( ε' ) of Ba 2 Co 2 Mn x Fe 12- x O 22 ferrites decreases with increasing ×, which can be attributed to the formation of a stable ion pair (Mn 3+ - Fe 2+ ) due to the doped Mn ions entering the octahedral (B) sites. The real part of complex permeability constant ( μ' ) of ferrites increases with the increase of Mn substitution due to the decreased magneto-crystalline anisotropy. The effective absorption bandwidth (EAB) of ferrites increases from 5.5 GHz to 9.1 GHz with the increase of Mn substitution from x = 0 to 1.6, significantly improving microwave absorption performance. The EAB of Ba 2 Co 2 Mn x Fe 12- x O 22 ferrite at x = 1.2 reaches 8.74 GHz at a thickness of only 1.57 mm, which could be employed as microwave absorbers due to its broad bandwidth, strong absorption, and small thickness. The excellent performance is mainly attributed to the synergy effect of multiple reflections, natural resonance, dipole polarization and good impedance matching.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Dezhi Wang,Jiasen Wang,Xuebao Li,Cheng Han,Hao Fei,Zhuangzhi Wu
In the pursuit of enhancing the energy density of lithium-ion batteries, cathode prelithiation emerges as a pivotal approach, introducing additional irreversible active lithium ions to augment performance. Li 5 FeO 4 (LFO) stands out as an excellent option, boasting an impressive theoretical specific capacity and the additional advantages of cost-effectiveness in raw materials and low preparation cost. However, the impact of extra lithium incorporations on compositional changes at the electrode-electrolyte interface as well as on cell stability has impeded further researches. Herein, a Mn doping strategy is proposed and predicted by first-principles calculations to synthesize partially Mn-substituted Li 5.125 Fe 0.875 Mn 0.125 O 4 (LFMO). And the prelithiation with LFMO improved the interfacial composition of LiFePO 4 (LFP) batteries compared to LFO, achieving a charging capacity of 213 mAh∙g −1 in the first cycle at 0.05 C. The subsequent treatment demonstrated superior cycling stability, maintaining a discharge specific capacity as high as 155.3 mAh∙g −1 after 100 cycles at 0.2 C, and exhibiting a higher capacity retention in the full cell. These discoveries could contribute to enhancing the regulation of battery interface during the utilization of LFO, potentially promoting the development of cathode lithium additives.
研究领域:
材料科学
·
电化学
·
电池技术
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2018
·
IF 4.229
Xiubing Huang,Jie Feng,Hassan R.S. Abdellatif,Jing Zou,Guan Zhang,Chengsheng Ni
Mn-substituted double perovskites , PrBaCo 2-x Mn x O 5+δ (x = 0, 0.5, 1), are evaluated as cathode materials for intermediate-temperature solid oxide fuel cells. The effects of Mn substitution content on their structural and electrochemical properties including crystal structure, thermal expansion coefficient , and cathodic interfacial polarization resistance are investigated. The PrBaCo 2-x Mn x O 5+δ samples exhibit structural changes with increasing Mn contents from tetragonal (x = 0) to cubic (x = 0.5 and 1.0) symmetry. The thermal expansion coefficient decreases with the increasing Mn content while the cathodic performance increases with the increment of Mn content from x = 0 to x = 0.5 then decreases with the further increment of Mn content from x = 0.5 to x = 1.0. When using La 0.8 Sr 0.2 Ga 0.8 Mg 0.15 Co 0.05 O 3 with 300 μm thickness as electrolyte and Sr 2 Fe 1.4 Ni 0.1 Mo 0.5 O 6-δ as anode, the maximum powder density of the x = 0.5 composite is 0.638 W cm −2 , which is higher than that of the other two samples with x = 0 (0.474 W cm −2 ) and x = 1.0 (0.371 W cm −2 ) at 800 °C.
研究领域:
材料科学
·
能源工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Environmental Science-Nano
·
2019
·Vol. 6
·期 5
·1406-1417
·
IF 7.704
Yili Xie,Chen Tian,Weiyi Chen,Can Wu,Zhangbin Liu,Ping Ning,Hong Deng,Zhang Lin
Manganese ferrite (MnxFe3−xO4) microspheres with a spinel structure are very effective adsorbents for arsenic (As) removal. In this study, highly ordered mesoporous MnxFe3−xO4 has been synthesized by a facile and convenient solvothermal method. By comparing the different doping amounts of manganese (Mn), the results show that Mn1.8Fe1.2O4 has a relatively higher efficiency for arsenate (As(V)) removal due to the modified surface complexes caused by the optimum Mn substitution. Rietveld XRD refinement reveals that Mn1.8Fe1.2O4 microspheres possess the highest distribution ratio of Mn/Fe situated between the octahedral (Oh) and the tetrahedral (Td) sites of the unit cell. The as-prepared Mn1.8Fe1.2O4 microspheres with MnO6Oh sites in Fdm symmetry exhibit a promising ability for toxic As(V) adsorption, which is mainly attributed to the increase of coordinated complexes. Extended X-ray absorption fine structure (EXAFS) analysis indicates that the coordination structures of As(V) on Mn1.8Fe1.2O4 are present as bidentate binuclear complexes with a regular distance of As–Fe = 3.41 Å. Apart from this, As(V) can also bind with Mn-doped sites through the monodentate coordination mode at a distance of As–Mn = 3.51 Å with a preferred coordination number (CN) of 4.4. This work discloses the correlation between the superior As(V) adsorption ability and MnO6Oh sites in Mn1.8Fe1.2O4 and provides an emerging and promising method to enhance the adsorption capacity of As via modifying Mn doping sites based on the pollutant structure to achieve synergistic adsorption effects.
研究领域:
环境科学
·
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）