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A novelty strategy induced pinning effect and defect structure in Ni-rich layered cathodes towards boosting its electrochemical performance

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Journal of Energy Chemistry 2022年第9期31卷 570-580,I0016页

作者： Zhouliang Tan Yunjiao Li Xiaoming Xi Shijie Jiang Xiaohui Li Xingjie Shen Panpan Zhang Zhenjiang He Junchao Zheng School of Metallurgy and Environment Central South UniversityChangsha 410083HunanChina Engineering Research Center of the Ministry of Education for Advanced Battery Materials Central South UniversityChangsha 410083HunanChina Changsha Research Institute of Mining and Metallurgy Changsha 410083HunanChina Office of Laboratory and Equipment Management Xinjiang UniversityUrumqi 830000XinjiangChina

Layered Ni-rich transition metal oxide is treated as the most promising alternative cathode due to their high-capacity and flexible composition.However,the severe lattice strain and slow Li-ion migration kinetics severely restrict their practical application.Herein,a novelty strategy induced pinning effect and defect structure in layered Ni-rich transition metal oxide cathodes is proposed via a facile cation(iron ion)/anion(polyanion)co-doping method.Subsequently,the effects of pinning effect and defect structure on element valence state,crystal structure,morphology,lattice strain,and electrochemical performance during lithiation/delithiation are systematically explored.The detailed characterizations(soft X-ray absorption spectroscopy(sXAS),in-situ X-ray diffraction(XRD),etc.)and density functional theory(DFT)calculation demonstrate that the pinning effects built-in LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)materials by the dual-site occupation of iron ions on lithium and transition metal sites effectively alleviate the abrupt lattice strain caused by an unfavorable phase transition and the subsequent induction of defect structures in the Li layer can greatly reduce the lithium-ion diffusion barrier.Therefore,the modified LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)exhibits a high-capacity of 206.5 mAh g^(-1)and remarkably enhanced capacity retention of 93.9%after 100 cycles,far superior to~14.1%of the pristine cathodes.Besides,an excellent discharge capacity of 180.1 mAh g^(-1)at 10 C rate is maintained,illustrating its remarkable rate capability.This work reports a pinning effect and defect engineering method to suppress the lattice strain and alleviate lithium-ion kinetic barriers in the Ni-rich layered cathodes,providing a roadmap for understanding the fundamental mechanism of an intrinsic activity modulation and structural design of layered cathode materials.

关键词： Ni-rich layered cathode Pinning effect defect structure Lattice strain Lithium-ion kinetic

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Modified NiFe-MOF with defects induced by-NH_(2)and-SH for enhanced adsorption and photocatalytic reduction of CO_(2)

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Journal of Materials Science & Technology 2024年第3期170卷 167-176页

作者： Ruting Huang Yeyin Zhang Wenqiang Li Wanxia Zhang Yong Fang Wenrui Zhang Anqi Cui Yu Ying Xianyang Shi Information Materials and Intelligent Sensing Laboratory of Anhui Province Anhui Province Key Laboratory of Wetland Ecosystem Protection and RestorationSchool of Resource and Environmental EngineeringAnhui UniversityHefei230601China Key Laboratory of Nutrient Cycling Resources and Environment of Anhui Institute of Soil and FertilizerAnhui Academy of Agricultural SciencesHefei230001China

In this study,a Ni-Fe metal-organic framework modified by-NH_(2)and-SH was synthesized using a sim-ple hydrothermal process for enhancing photocatalytic CO_(2)reduction.As expected,the N2S-NiFe(NH_(2)-BDC/H_(4)DSBDC,2:1)displayed excellent photocatalytic CO_(2)reduction activity and high CO selectivity(12,412.23μmol g^(−1)h^(−1))under visible light irradiation(λ≥420 nm),which is 5 times that of NiFe-MOF.Notably,the excellent photocatalytic performance of N2S-NiFe can benefit from the rich defect trap site caused by the introduction of amino and sulfhydryl groups,accelerating charge transfer and promoting space charge separation,as supported by the photo-electrochemical properties.To better understand the CO_(2)adsorption mechanism,density functional theory calculations were performed,which revealed that the Niov site has more negative adsorption energy compared with the Feov site.This study provides a simple strategy to establish efficient photocatalysts for CO_(2)reduction through the modification of organic ligands.

关键词： NiFe-MOF CO_(2)reduction defect structure Photocatalytic

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Hierarchical Fe_(x)Bi_(2−x)S_(3) solid solutions for boosted supercapacitor performance

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Nano Research 2024年第5期17卷 3997-4005页

作者： Fengming Zhou Xiaodong Wang Ruijie Jing Xiaoyu Li Qi Zhang Zhenjiang Li Yunmei Du Zhenyu Xiao Lei Wang International Cooperation United Laboratory of Eco-chemical Engineering and Green Manufacturing College of Chemistry and Molecular EngineeringQingdao University of Science and TechnologyQingdao 266042China Technology Innovation Center of Battery Safety and Energy Storage Technology QingdaoInternational Science and Technology Cooperation Base of QingdaoCollege of Environment and Safety EngineeringQingdao University of Science and TechnologyQingdao 266042China

For the pursuit of high energy supercapacitors,the development of high performance pseudocapacitance or battery-type negative electrode material is urgently needed to make up for the capacity shortage of commercial electric double layer capacitor(EDLC)type materials.Herein,a porous and defect-rich Fe_(x)Bi_(2-x)S_(3) solid solution structure is firstly constructed by employing Fe-doped Bi_(2)O_(2)CO_(3) porous nanosheets as a precursor,which presents dramatically increased energy storage performance than Bi_(2)S_(3) and FeS_(2) phase.For the optimized Fe_(x)Bi_(2-x)S_(3) solid solution(FeBiS-60%),the Fe solute is free and random dispersed in Bi_(2)S_(3) framework,which can effectively modulate the electronic structure of Bi element and introduce rich-defect due to the existence of Fe(II).Meanwhile,the FeBiS-60%,constructed by pore nanosheets that are assembled by self-supported basic nanorod units,presents rich mesoporous channels for fast mass transfer and abundant active sites for promoting capacity performance.Therefore,a high capacitance of 832.8 F·g^(-1) at a current density of 1 A·g^(-1) is achieved by the FeBiS-60%electrode.Furthermore,a fabricated Ni3S_(2)@Co_(3)S_(4)(NCS)//FeBiS-60%hybrid supercapacitor device delivers an outstanding energy density of 85.33 Wh·kg^(-1) at the power density of 0.799 kW·kg^(-1),and ultra-long lifespan of remaining 86.7%initial capacitance after 8700 cycles.

关键词： supercapacitor solid solutions defect structure hierarchical structure Bi_(2)S_(3)

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Atomistic Simulation Study of defect structure of Zircon as a High-Level Nuclear Waste Host Form

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Journal of Earth Science 1999年第4期18卷 309-313页

作者： He Yong(Faculty of Material Sciences and Chemical Engineering, China University of Geosciences,Wuhan 430074, P. R. China)Cormack A. N.(New York State College of Ceramics at Alfred University, Alfred, NY, 14802, USA) Faculty of Material Sciences and Chemical Engineering China University of GeosciencesWuhan 430074P.R. China New York State College of Ceramics at Alfred University AlfredNY14802USA

A set of potential parameters for modeling zircon was obtained by atomistic simulation techniques and a reasonable structural model of zircon was established by fitting some important properties of zircon.Based on the equilibrium configuration of zircon, authors calculated the formation energies of basic point defects and intrinsic disorders. The heats of solution of substituting Pu for Zr showed that there was an immiscible gap at the composition of (Pu75%-Zr25%, in mole fraction), which suggests that the amount of Pu substituting for Zr in zircon be≤50%.

关键词： zircon nuclear waste host atomistic simulation technique defect structure

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Enhanced electrocatalytic activity of Co@N-doped carbon nanotubes by ultrasmall defect-rich TiO2 nanoparticles for hydrogen evolution reaction

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Nano Research 2017年第8期10卷 2599-2609页

作者： Jiayuan Yu Weijia Zhou Tanli Xiong Aili Wang Shaowei Chen Benli Chu School of Environment and Energy Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control South China University of Technology Guangzhou Higher Education Mega Center Guangzhou 510006 China School of Physics and Telecommunication Engineering South China Normal University Guangzhou Higher Education Mega Center Guangzhou 510006 China Department of Chemistry and Biochemistry University of California 1156 High Street Santa Cruz CA 95064 USA

Despite being technically possible, splitting water to generate hydrogen is practically unfeasible, mainly because of the lack of sustainable and efficient earth-abundant catalysts for the hydrogen-evolution reaction （HER）. Herein, we report a durable and highly active electrochemical HER catalyst based on defect-rich TiO2 nanoparticles loaded on Co nanoparticles@N-doped carbon nanotubes （D-TiOdCo@NCT） synthesized by electrostatic spinning and a subsequent calcining process. The ultrasmall TiO2 nanoparticles are 1.5-2 nm in size and have a defect-rich structure of oxygen vacancies. D-TiO2/Co@NCT exhibits excellent HER catalytic activity in an acidic electrolyte （0.5 M H2SO4）, with a low onset potential of -57.5 mV （1 mA·cm^-2）, a small Tafel slope of 73.5 mV·dec^-1, and extraordinary long-term durability. X-ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy, and theoretical calculations confirm that the Ti3. defect-rich structure can effectively regulate the catalytic activity for electrochemical water splitting.

关键词： ultrasmall nanoparticle TiO2 defect structure carbon nanotube hydrogen-evolution reaction

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Enhanced thermal and cycling reliabilities in (K,Na)(Nb,Sb)O3-CaZr03-(Bi,Na)Hf03 ceramics

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Journal of Advanced Ceramics 2020年第3期9卷 349-359页

作者： Yi FAN Zhenxing WANG Yu HUAN Tao WEI Xiaohui WANG School of Material Science and Engineering University of JinanJinan 250022China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

The thermal stability and fatigue resistance of piezoelectric ceramics are of great importance for industrialized application.In this study,the electrical properties of(0.99-x)(K0.48Na0.52)Nb0.975Sb0.025)O3-0.01CaZrO3-x(Bi0.5Na0.5)HfO3 ceramics are investigated.When x=0.03,the ceramics exhibit the optimal electrical properties at room temperature and high Curie temperature(Tc=253℃).In addition,the ceramic has outstanding thermal stability(d33≈301 pm/V at 160℃)and fatigue resistance(variation of Pr and d33~10 %after 10^4 electrical cycles).Subsequently,the defect configuration and crystal structure of the ceramics are studied by X-ray diffraction,temperature-dielectric property curves and impedance analysis.On one hand,the doping(Bio sNao.3)HfO3 makes the dielectric constant peaks flatten.On the other hand,the defect concentration and migration are obviously depressed in the doped ceramics.Both of them can enhance the piezoelectrical properties and improve the temperature and cycling reliabilities.The present study reveals that the good piezoelectric properties can be obtained in 0.96(K0.58Na0.52)(Nb0.975Sb.025)O3-0.01CaZrO3-0.03(Bi0.5Na0.5)HfO3 ceramics.

关键词： (Na,K)NbO3(KNN)-based ceramics thermal stability fatigue resistance crystal structure defect structure

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Mosaic structure Evolution in GaN Films with Annealing Time Grown by Metalorganic Chemical Vapour Deposition

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Chinese Physics Letters 2006年第5期23卷 1257-1260页

作者：陈志涛徐科郭立平杨志坚潘尧波苏月永张酣沈波张国义 School of Physics Peking University Beijing 100871 State Key Laboratory for Artificial Microstructure and Mesoscopic Physics Peking University Beijing 100871 Research Center for Wide-band Semiconductors Peking University Beijing 100871 Beijing Synchrotron Radiation Facility Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049

We investigate mosaic structure evolution of GaN films annealed for a long time at 800℃ grown on sapphire substrates by metalorganic chemical vapour deposition by high-resolution x-ray diffraction. The result show that residual stress in GaN films is relaxed by generating edge-type threading dislocations （TDs） instead of screw-type TDs. Compared to as-grown GaN films, the annealed ones have larger mean twist angles corresponding to higher density of edge-type TDs but smaller mean tilt angles corresponding to lower density of screw-type TDs films. Due to the increased edge-type TD density, the lateral coherence lengths of the annealed GaN films also decrease. The results obtained from chemical etching experiment and grazing-incidence x-ray diffraction （GIXRD） also support the proposed structure evolution.

关键词： THREADING DISLOCATIONS defect structure EPITAXIAL GAN THIN-FILMS

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structure and Magnetic Property of Amorphous Fe-Ni Particles Prepared by Mechanical Alloying

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Journal of Shanghai University(English Edition) 2001年第2期5卷 147-150页

作者： XUShi－yue HEZheng－ming 等 DepartmentofPhysics CollegeofSciencesShanghaiUniversityShanghai200436China

The amorphous Fe 67.5 Ni 32.5 alloy particles have been prepared by mechanical alloying (MA) process of elemental powders. The crystallization is observed at temperature around 405°C by means of differential thermal analyzer. It is found that the coercivity H C and the effective magnetic anisotropy value of amorphous phase are not far from that of crystal phase. The magnetization behavior of amorphous and nanocrystalline samples prepared by mechanical alloying and milling process are quite similar, they obey 1/H law at middle high field and 1/H 2 at higher field. The 1/H field dependence is attributed to a large number of dislocations created during MA process. The studies on the 1/H 2 field dependence reveals that magnetization of Fe Ni ultrafine particles are governed predominantly by internal stress fields induced by MA process.

关键词： mechanical alloying amorphous ultrafine particles defect structure

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