ACS Nano
·
2024
·
IF 15.8
Zhongxing Xu,Xinghan Chen,Wenguang Fan,Minzhi Zhan,Xulin Mu,Hongbin Cao,Xiaohu Wang,Haoyu Xue,Zhihai Gao,Yongzhi Liang,Jiajie Liu,Xinghua Tan,Feng Pan
Single-crystalline Ni-rich layered oxides are one of the most promising cathode materials for lithium-ion batteries due to their superior structural stability. However, sluggish lithium-ion diffusion kinetics and interfacial issues hinder their practical applications. These issues intensify with increasing Ni content in the ultrahigh-Ni regime (≥90%), significantly threatening the practical viability of the single-crystalline strategy for ultrahigh-Ni layered oxide cathodes. Herein, by developing a high-entropy coating strategy, we successfully constructed an epitaxial lattice-coherent high-entropy rock-salt layer (∼3 nm) via Zr and Al doping on the surface of the single-crystalline cathode LiNi0.92Co0.05Mn0.03O2 through an in situ modification process. The surface high-entropy rock-salt layer with tailored Ni valence and lattice coherence not only greatly improves lithium-ion diffusion kinetics but also suppresses interface parasitic reactions and surface structural degradations. The high-entropy surface layer-stabilized ultrahigh-Ni single-crystalline cathode (SC-Ni92-ZA) demonstrates significantly improved rate and cycling performances (127.5 mAh g–1 at 20C, capacity retention of 74.9% after 500 cycles at 1C) in a half-cell. The SC-Ni92-ZA exhibits a capacity retention of 87.1% after 600 cycles at 1C in a full-cell. This epitaxial lattice-coherent high-entropy coating strategy develops a promising avenue for developing high-capacity, long-life cathode materials.
研究领域:
材料科学
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电化学
·
能源存储
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Junjun Tang,Shuan Ma,Yu Jiang,Lufeng Yang,Jie Chen,Xuemin Yan,Bohong Chen,Zhenxiong Huang
The inferior cycling stability of MnO 2 -based cathodes, resulting from Mn dissolution and crystal structure transition during Zn-ion insertion/extraction, poses a significant challenge hindering their widespread adoption in aqueous zinc-ion batteries (AZIBs). To mitigate these issues, we propose an approach involving the incorporation of small organic molecules (methylformamide, dimethylformamide, and formamide) to modify the crystalline structure of MnO 2 . These molecules, characterized by their low orbital energy levels, facilitate the creation of energetically equivalent electron transfer pathways with the unoccupied e g orbitals in Mn 4+ , as evidenced by the DFT calculations. Furthermore, they modulate the electron cloud density of Mn-O and introduce structural disorder in the MnO 2 crystalline lattice, thereby greatly enhancing the structural stability of the Mn-based cathode. In AZIBs tests, the MnO 2 /methylformamide (MO/NMF) cathode demonstrates a remarkable reversible specific capacity exceeding 270 mAh g -1 at 1 A g -1 and exceptional durability, exhibiting negligible capacity degradation after 2000 cycles at 3 A g -1 . In-situ X-ray diffraction, neutron powder diffraction and high-angle annular dark-field scanning transmission electron microscopy analyses confirm the structure stability of MO/NMF during Zn-ion insertion/extraction, attributed to the NMF modification. Additionally, the electrochemical data indicate that modifications with dimethyl formamide and formamide also positively impact the electrochemical performance of the MnO 2 cathode. This study offers valuable insights for the development of high-performance Mn-based cathodes.
研究领域:
材料科学
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电化学
·
能源存储
✓ 已验证
DOI
高影响因子
IONICS
·
2024
·Vol. 30
·期 8
·4479-4486
·
IF 2.4
Tang Anping,Chen Juedong,Xu Guorong,Song Haishen,Wang Jinglun,Chen Hezhang
Non-intercalation cathode materials based on nanocomposites of lithium fluoride and Li-free transition metal compounds have drawn attention as materials for fabricating the cathode of lithium ion batteries owing to their high theoretical specific capacities and high redox voltages. In the present study, a nanocomposite of MnO-LiF was in situ synthesized by a quick annealing at 500 °C for just 5 min using a mixture of ammonium fluoride, manganese acetate, and lithium acetate as precursor. The synthesized composite is investigated by X-ray diffraction, scanning electron microscopy, nitrogen sorption, and charge-discharge measurements. As a lithium-ion battery cathode, it delivers respectively an initial discharge-specific capacity of 170 mAh g −1 and a discharge-specific capacity of 137 mAh g −1 in the 50th cycle at a current rate of C/20, which is equivalent to a moderate capacity retention rate of 80.6%. The novel synthesis approach proposed offers access to electrochemically active composites of lithium fluoride and Li-free transition metal oxides.
研究领域:
材料科学
·
电化学
·
纳米复合材料
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能源存储
·
锂离子电池
✓ 已验证
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2019
·Vol. 6
·期 4
·1011-1021
·
IF 5.934
Junping Ma,Qiuyu Zhao,Dongli Wei,Haiqiang Liu,Xiangke Wang,Zhe Chen,Jianjun Wang
The adsorption remediation of radioactive contamination from wastewater is scientifically and economically important. In this work, titanium dioxide-modified manganese dioxide (MnO2@TiO2) was prepared by immobilizing crystalline anatase titanium dioxide (TiO2) on the surface of alpha manganese dioxide nanowire (MnO2). The base material MnO2 nanowire acted as a physical template for the guest TiO2, and the formed MnO2@TiO2 composite exhibited a highly uniform core–shell nanorod structure. The MnO2@TiO2 composite was investigated as an efficient adsorbent for the removal of U(VI) from aqueous solution. In the same system, MnO2@TiO2 exhibited a much higher maximum adsorption capacity (105.3 mg g−1) for U(VI) as compared with MnO2 (13.3 mg g−1), showing that the performance of the surface-modified MnO2 was greatly improved. The fitting results for kinetic and isothermal models manifested that U(VI) ion adsorption by MnO2@TiO2 involved monolayer chemisorption. Characterization before and after adsorption was performed and the results compared and analyzed carefully, with the conclusion that there might be three kinds of interactions between U(VI) and MnO2@TiO2 during the adsorption process, namely inner-sphere surface complexation, chemical precipitation, and electrostatic interaction. The low-cost, facile fabrication method and efficient performance endow the adsorbent MnO2@TiO2 with a high potential for U(VI) removal from actual wastewater.
研究领域:
环境科学
·
材料科学
·
核废物处理
·
水污染控制
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2018
·Vol. 21
·期 3
·470-477
·
IF 3.304
Huihua Peng,Chuan Jing,Jie Chen,Deyi Jiang,Xiaoying Liu,Biqin Dong,Fan Dong,Shaochun Li,Yuxin Zhang
Rational design of the crystal structures of electrode materials is considered as an important strategy to construct high-performance supercapacitors. Herein, the three-dimensional crystal structure NiMn LDH@Co3O4 composites on Ni foam with different feeding Ni/Mn molar ratios were well-designed with hydrothermal, calcination and co-deposition methods, wherein urea hydrolysis supplied the alkali and carbonate ions. The electrochemical properties of the produced electrode materials were analyzed by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), electrochemical impedance spectroscopy (EIS) and cycling stability tests using 6 M KOH electrolyte. Indeed, the optimal feeding Ni/Mn molar ratio was determined to be 3 : 1. The resulting electrodes exhibited maximum specific capacitance (607.9 F g−1 at 0.5 A g−1), respectable rate capability and excellent cycling stability with less than 3% loss of capacitance after 1000 cycles, which could be ascribed to the well-designed core–shell architecture and ultrathin nanosheets structure of LDH. As for practical application, the asymmetric supercapacitor assembled using NiMn LDH@Co3O4 as the positive electrode and activated graphene (AG) as the negative electrode was also evaluated, which demonstrated a high energy density of 26.49 W h kg−1 at the power density of 350 W kg−1. The findings suggest that the three-dimensional crystal structure NiMn LDH@Co3O4 composites have potential application as promising electrode materials for energy storage devices or other applications.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Chen Yang,Xinhua Chen,Minmin Mao,Xinjiang Luo,Weiqin Sheng,Zhilun Lu,Shikuan Sun,Hong He,Weitao Su,Kaixin Song
Orange-yellow luminescent Y 2- x Sr 1- y Al 4 SiO 12 : x Ce 3+ , y Mn 2+ ( x = 0.04–0.06, y = 0.1–0.6, abbreviated as YSAS: x Ce 3+ , y Mn 2+ ) phosphors with garnet structure were prepared by the high temperature solid-phase method. The matrix energy band is calculated by DFT , where YAG is 4.535 e V and YSAS is 4.874 e V. The Rietveld refinement of the XRD data indicates that Ce 3+ mainly replaces the Y 3+ sites, while Mn 2+ selectively occupies. The Gaussian peaks of the fluorescence spectrum prove that Mn 2+ occupies two luminescent centers, which are further determined by Van Uitert's empirical formula. The doping of Ce 3+ /Mn 2+ units can effectively enhance the structural rigidity of the YAG host and promote the red-shift of the emission peak position of Mn 2+ . The fluorescence decay kinetics test proves that Ce 3+ can transfer energy to Mn 2+ , and the transfer efficiency reaches 72.08% at y = 0.5. The thermal stability test of the phosphor shows the luminous intensity at 473 K still maintains 86% of the room temperature . The phosphor prepared in this experiment was combined with a blue light chip to make a w-LED device, and the performance showed Ra = 86.1, CCT = 5168 K. The above results show that the emission color of the garnet structure can be tuned by energy transfer, which is attractive for future applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 10
·期 6
·2095-2102
·
IF 8.067
Guojun Zhou,Jialiang Ding,Xingxing Jiang,Jian Zhang,Maxim S. Molokeev,Qiqiong Ren,Jun Zhou,Shili Li,Xian-Ming Zhang
Organic–inorganic metal halides have become a multifunctional platform for manipulating photoluminescence due to highly efficient and tunable emissions, especially for lead-free Mn2+-based halides. Herein, the zero-dimensional (0D) bromides of (C5H14N3)2MnBr4 and (CH6N3)2MnBr4 with different coordination environments were designed and synthesized by a solvent evaporation method. They exhibit green and red broadband emission peaks at 528 nm and 627 nm with high photoluminescence quantum yields of 86.83% and 61.91%, respectively, which are attributed to the d–d transition (4T1(G) → 6A1(S)) of [MnBr4]2− tetrahedral and [Mn3Br12]6− octahedral units. The cases emphasize the effect of organic ligands on the intrinsic emissions of Mn2+ ions, thereby revealing the luminescence mechanism of Mn2+ ions in 0D isolated structures through the Tanabe–Sugano (TS) energy diagram. Thanks to their bright and stable emissions, the fabricated white light-emitting diode (LED) based on (C5H14N3)2MnBr4 and (CH6N3)2MnBr4 provides an outstanding color rendering index (Ra) of 90.8 at a correlated color temperature (CCT) of 3709 K, along with the CIE chromaticity coordinates of (0.3985, 0.3979) and a luminous efficacy of 51.2 lm W−1. This work aims at clarifying the relationship between the coordination units of Mn2+ and tunable emissions, and in particular, proposes a new strategy to explore phosphors excited by blue light for white LEDs.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Mengfan Luo,Heng Zhang,Jianhua Guo,Jia Zhao,Can Feng,Jialong Yin,Chang Xu,Ye Du,Yang Liu,Chuan-Shu He,Bo Lai
Redox-inactive metal-ion-driven modulation of the oxidation behavior of high-valent metal–oxo complex has garnered significant interest in biological and chemical synthesis; however, their role in permanganate (Mn(VII)) oxidation for the removal of organic pollutants has been largely neglected. Here, we uncover the impact of six metal ions (i.e., Ca2+, Mg2+, Ni2+, Zn2+, Al3+, and Sc3+) presenting in water environments on Mn(VII) activity. These ions uniformly boost the electron and oxygen transfer capabilities of Mn(VII) while impeding proton transfer, as evidenced by electrochemical tests, thioanisole probe analysis, and the kinetic isotope effect. The observed effects are intricately linked to the Lewis acidity of the metal ions. Further mechanistic insights reveal that Mn(VII) can interact with metal ions without direct reduction. Such interactions modify the electronic configuration of Mn(VII) and create an acidic microenvironment, thus increasing its electrophilicity and the energy barrier for the abstraction of proton from organic substrates. More importantly, the efficacy of Mn(VII) in removing phenolic pollutants is regulated by these ions through changing the driving force for proton and electron transfer, i.e., facilitated at pH > 4.5 and inhibited at lower pH. The contribution of active Mn intermediates is also discussed to reveal the oxidative mechanism of the metal ion/Mn(VII) system. These findings not only facilitate the rational design of Mn(VII) oxidation conditions in the presence of metal ions for water decontamination but also offer an alternative paradigm for enhancing electrophilic oxidation.
研究领域:
环境科学
·
化学动力学
·
水处理技术
✓ 已验证
DOI
PubMed
高影响因子
Surfaces and Interfaces
·
2022
·
IF 6.137
Shaomei Linghu,Ziyong Wu,Yuan Zhu,Huaju Song,Ying Wang,Zhiping Zhou,Yun Shan
To obtain semiconductor nanocrystals (NCs) with strong anodic electrochemiluminescence (ECL) remains a challenge due to their insufficiency to resist following corrosion upon holes injection to the NCs. Herein, we report strong and stable anodic ECL generated from 0.8 at% Mn 2+ doped CdS NC films on indium tin oxide (ITO) electrode in the presence of coreactant triethanolamine (TEOA) under potential scan to +1.5 V vs. saturated calomel electrode (SCE), which is much more negative than the valence band potential of host NCs. The Mn 2+ doping leads to an 8-fold enhancement in anodic ECL intensity in comparison with undoped CdS NC films due to efficient Mn excitation via nonradiative recombination energy transfer, i.e., exchange recombination. The efficiency is dependent on Mn 2+ doping amount as well as applied potential for holes injection with the maximum obtained when the charge transfer to Mn dopants is possible and the energy gap between conduction band and applied potential matches with Mn excitation. This anodic ECL was used to detect dopamine, a model analyte, showing a wide linear range from 5 nM to 1 μM with a detection limit of 1 nM at S/N=3. This work provides a new insight into ECL generation in doped semiconductor NCs. The Mn 2+ doped CdS NCs passivated by carboxylic groups display great potential in future development of biosensors .
研究领域:
分析化学
·
材料科学
·
生物传感
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Fangbao Fu,Xueqing Qiu,Dongjie Yang
Carbon/transition metal oxide composites exhibit promising potential as electrode materials for energy storage, but regulating their interfacial composite structures remains a formidable challenge. In this work, we develop a lignosulfonate-assisted synthesis strategy to fabricate a porous carbon-supported MnO2 composite (LSC/MnO2-2) with a robust interface for asymmetric supercapacitors (ASCs). The functionalized lignin porous carbon, achieved through π–π interactions with lignosulfonate, exhibited improved dispersibility, thereby facilitating the deposition of MnO2 onto the carbon matrix. Consequently, LSC/MnO2-2 demonstrates uniform MnO2 loading and enhanced interfacial bonding. The robust interaction between Mn sites and the lignosulfonate-functionalized carbon substrate can promote electron transfer and ion transfer kinetics, effectively activating the electrochemical activity of MnO2. The as-prepared LSC/MnO2-2 demonstrates high specific capacitances of 750 F/g at 0.5 A/g and 400 F/g at 10.0 A/g in a 1 M KOH electrolyte. Furthermore, the assembled ASC exhibits an outstanding energy density of 54.4 Wh/kg at 998.2 W/kg and excellent cyclic stability (94.7% retention over 10,000 cycles at 2.0 A/g). This study presents an alternative method to precisely control the deposition of metal oxides onto carbon materials, aiming to enhance the performance of carbon composites.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Chengwang Yin,Shujun Qiu,Yongpeng Xia,Fen Xu,Lixian Sun,Hailiang Chu
Magnesium hydride (MgH 2 ) stands out as a promising solid-state material for high-density hydrogen storage , offering enormous potential for applications in hydrogen transportation and storage. However, the stable thermodynamics and sluggish kinetics of dehydrogenation/hydrogenation of MgH 2 impede its practical use in on-board hydrogen storage. In this study, the nanocomposite of nickel/manganese oxide (Ni/MnO) was successfully synthesized through the hydrogenation of nickel-manganese two-dimensional layered double hydroxide (NiMn-LDH) and then introduced into MgH 2 by ball milling to form BM-MgH 2 -Ni/MnO composite. Notably, BM-MgH 2 -Ni/MnO-10 displayed excellent hydrogen absorption/dehydrogenation properties. For example, its onset hydrogen release temperature was remarkably reduced to 175.6 °C, 84 °C lower than that of BM-MgH 2 . At a temperature of 250 °C, it could desorb about 6.2 wt% of H 2 within 60 min. The fully dehydrogenated product could absorb 5.5 wt% of H 2 within 10 min at 150 °C. Moreover, BM-MgH 2 -Ni/MnO-10 exhibited excellent cycling performance. Throughout the cycling process, the in-situ formation of Mg 2 Ni/Mg 2 NiH 4 and metal Mn was detected, leading to a synergistic effect that significantly enhanced the hydrogen storage capability of MgH 2 . This study presents innovative concepts for designing active catalysts to enhance the kinetics of de-/hydrogenation reactions of MgH 2 .
研究领域:
材料科学
·
氢能技术
✓ 已验证
DOI
高影响因子
Energy Material Advances
·
2022
·
IF 0
Renjie He,Sheng Lei,Mengchuang Liu,Mingsheng Qin,Wei Zhong,Shijie Cheng,Jia Xie
Microspinel LiMn2O4 (LMO) is a widely used cathode material in power lithium-ion batteries. However, inevitable Mn dissolution and dynamic phase instability will cause the degradation of microspinel LMO during cycling. Here, a low-tortuosity LMO (LMO-LT) electrode is fabricated by an ice-templating method, which exhibits enhanced dynamic phase stability, alleviated Mn dissolution, and rare particle microcracks during cycling. It is shown that the low-tortuosity electrode enables fast lithium-ion diffusion and thus small concentration polarization, leading to uniform electrochemical reaction within microregions of the LMO-LT electrode. Furthermore, the fast lithium-ion transport kinetics and even mesoscopic scale reactions of the LMO-LT electrode effectively alleviate irreversible phase transition and Mn dissolution as well as suppress crack generation in LMO particles. As a result, the full cell [negative-to-positive capacity ratio (N/P) = 1.1] with thick LMO-LT cathode (13 mg cm−2) and Li4Ti5O12 anode sustains 80.0% capacity over 200 cycles. The LMO-LT electrode further delivers 78.9% capacity of that at 0.1 C at the high rate of 5 C. This work provides an important strategy to enhance dynamic phase stability and suppress Mn dissolution at the mesoscopic scale, promoting the development of high-performance LMO electrodes.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
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