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Preparation of anatase TiO_2 with assistance of surfactant OP-10 and its electrochemical properties as an anode material for lithium ion batteries

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Rare Metals 2010年第5期29卷 505-510页

作者： YI Jin,TAN Chunlin,LI Weishan,LEI Jianfei,and HAO Liansheng School of Chemistry and Environment & Key Laboratory of electrochemical Technology on Energy Storage and Power Generation of Guangdong Higher Education Institutes,South China Normal University,Guangzhou 510006,China School of Chemistry and Environment & Key Laboratory of electrochemical Technology on Energy Storage and Power Generation of Guangdong Higher Education Institutes South China Normal University Guangzhou China

With the assistance of nonionic surfactant （OP-10） and surface-selective surfactant （CH3COOH）, anatase TiO2 was prepared as an anode material for lithium ion batteries. The morphology, the crystal structure, and the electrochemical properties of the prepared anatase TiO2 were characterized by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, electrochemical impedance spectroscopy （EIS）, and galvanostatic charge and discharge test. The result shows that the prepared anatase TiO2 has high discharge capacity and good cyclic stability. The maximum discharge capacity is 313 mAh.g^-1, and there is no significant capacity decay from the second cycle.

关键词： lithium ion batteries titanium dioxide sol-gel process electrochemical properties sttrfactants

Structure and electrochemical properties of La, F dual-doped LiLa_(0.01)Mn_(1.99)O_(3.99)F_(0.01) cathode materials

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Journal of University of Science and Technology Beijing 2008年第4期15卷 468-473页

作者： Meng Chen Shengjun Li Chuang Yang College of Material Science and Chemical Engineering Harbin Engineering University Harbin 150001 China

The cathode materials LiMn2O4 and rare earth elements La-doped or La and F dual-doped spinel lithium manganese *** synthesized by the citric acid-assisted sol-gel method. The synthesized samples were investigated by differential thermal analysis （DTA） and thermogravimetry （TG） measurements, X-ray diffraction （XRD）, scanning electronic microscope （SEM）, cyclic voltammetry （CV）, and charge-discharge test. XRD data shows that all the samples exhibit the same pure spinel phase, and the LiLa0.01Mn1.99O3.99F0.01 and ***.9904 samples have smaller lattice parameters and unit cell volume than LiMn2O4. SEM indicates that LiLa0.01Mn1.99O3.99F0.01 has a slightly smaller particle size and a more regular morphology structure with narrow size distribution. The charge-discharge test reveals that the initial capacities of LiMn2O4, LiLa0.01Mn1.99O4, and LiLa0.01Mn1.99O3.99F0.01 are 129.9, 122.8, and 126.4 mAh·g^-1, and the capacity losses of the initial values after 50 cycles are 14.5%, 7.6%, and 8.0%, respectively The CVs show that the La and F dual-doped spinel displays a better reversibility than LiMn2O4.

关键词： lithium ion battery cathode material LiMn2O4 structure electrochemical properties

Effect of carbon coating on electrochemical properties of AB_(3.5)-type La-Y-Ni-based hydrogen storage alloys

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Journal of Rare Earths 2022年第8期40卷 1264-1271页

作者： Ran Wu Huiping Yuan Yuru Liu Zhenyu Hou Zhinian Li Shumao Wang Lijun Jiang Lei Hao National Engineering Research Center of Nonferrous Metals Materials and Products for New Energy GRINM Group Co.Ltd.Beijing 100088China GRIMAT Engineering Institute Co. Ltd.Beijing 101407China General Research Institute for Nonferrous Metals Beijing 100088China Institute for Advanced Materials and Technology University of Science&Technology BeijingBeijing 100083China

The superlattice La-Y-Ni-based hydrogen storage alloys have high discharge capacity and are easy to ***,there is still a gap in commercial applications because of the severe corrosion of the alloys in electrolyte and poor high-rate dischargeability(HRD).Therefore,(LaSmY)(NiMnAl)_(3.5) alloy was prepared by magnetic levitation induction melting,and then the alloy was coated with different contents(0.1 wt%-1.0 wt%) of nano-carbons by low-temperature sintering with sucrose as the carbon source in this *** results show that the cyclic stability and HRD of the alloy first increase and then decrease with the increase of carbon *** kinetic results show that the electrocatalytic activity and conductivity of the alloy electrodes can be enhanced by carbon *** electrochemical properties of the alloy are the best when the carbon coating content is 0.3 wt%.Compared with the uncoated alloy,the maximum discharge capacity(C_(max)) improves from 354.5 to 359.0 mAh/g,the capacity retention rate after 300 cycles(S_(300)) enhances from 73.15% to 80.01%,and the HRD_(1200) of the alloy enhances from 74.39% to 74.39%.

关键词： La-Y-Ni-based alloy Sucrose Carbon coating electrochemical properties Ni/MH batteries Rare earths

Comparative structural and electrochemical properties of mixed P2/O′3-layered sodium nickel manganese oxide prepared by sol-gel and electrospinning methods:Effect of Na-excess content

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矿物冶金与材料学报:英文版 2023年第10期30卷 1887-1896页

作者： Thongsuk Sichumsaeng Atchara Chinnakorn Ornuma Kalawa Jintara Padchasri Pinit Kidkhunthod Santi Maensiri School of Physics Institute of ScienceSuranaree University of TechnologyNakhon Ratchasima 30000Thailand SUT CoE on Advanced Functional Materials Suranaree University of TechnologyNakhon Ratchasima 30000Thailand Research Network NANOTEC-SUT on Advanced Nanomaterials and Characterization Suranaree University of TechnologyNakhon Ratchasima 30000Thailand Synchrotron Light Research Institute(Public Organization) 111 University AvenueMuang DistrictNakhon Ratchasima 30000Thailand

The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess *** with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess *** analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,*** the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel *** contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 ***,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.

关键词： sodium nickel manganese oxide mixed P2/O′3-type Na-excess content sol-gel method electrospinning method electrochemical properties

Effects of annealing treatment on the microstructure and electrochemical properties of low-Co hydrogen storage alloys containing Cu and Fe

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Rare Metals 2011年第5期30卷 464-469页

作者： YANG Suxia LIU Zhiping HAN Shumin ZHANG Wei SONG Jianzheng State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004 China College of Environmental and Chemical Engineering Yanshan University Qinhuangdao 066004 China

The effects of annealing treatment on the microstructure and electrochemical properties of low-Co LaNi 3.55 Mn 0.35 Co 0.20 Al 0.20 Cu 0.75 Fe 0.10 hydrogen storage alloys were investigated. X-ray diffraction （XRD） analysis indicated that annealing treatment remarkably reduced the lattice strain and defects, and increased the unit-cell volume. The optical microscope analysis showed that the as-cast alloy had a crass dendrite microstructure with noticeable composition segregation, which gradually disappeared with increasing annealing temperature, and the micro-structure changed to an equiaxed structure after annealing the alloy at 1233 K. The electrochemical tests indicated that the annealed alloys demonstrated much better cycling stability compared with the as-cast one. The capacity retention at the 100th cycle increased from 90.0% （as-cast） to 94.7% （1273 K）. The annealing treatment also improved the discharge capacity. However, the high rate dischargeability （HRD） value of the annealed alloy slightly dropped, which was believed to be ascribed to the decreased exchange current density and the hydrogen diffusion coefficient in alloy bulk.

关键词： hydrogen storage alloys annealing phase structure microstructure electrochemical properties

Influences of Ti substitution on the structure and electrochemical properties of Mg_(1-x)Ti_xNi(x=0,0.1, 0.2, and 0.3) hydrogen storage alloys

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Rare Metals 2009年第5期28卷 504-510页

作者： HUANG Hongxia HUANG Kelong LIU Suqin CHEN Dongyang College of Chemistry and Chemical Engineering Central South University Changsha 410083 China Department of Materials and Chemical Engineering Guilin University of Technology Guilin 541004 China

MgNi-based hydrogen storage alloys Mg1–xTixNi （x = 0, 0.1, 0.2, and 0.3） were prepared by means of mechanical alloying. Mg in the alloy was partially substituted by Ti to improve the cycle stability of the alloys. The effects of the substitution of Ti for Mg on the microstructure and electrochemical performances of the alloys were investigated in detail. The results indicate that the substitution of Ti for Mg obviously decreases the discharge capacity, but it significantly improves their cycle stabilities. The microstructure of the alloys analyzed by X-ray diffraction （XRD） and scanning electron microscopy （SEM） shows that the alloys have a dominatingly amorphous structure. The substitution of Ti for Mg helps to improve the anti-oxidation/corrosion ability of the MgNi alloy but demolishes the electrochemical kinetics of hydrogenation/dehydrogenation. The Mg0.9Ti0.1Ni alloy electrode milled for 80 h exhibits the best integrative capability, which has the maximal discharge capacity of 331.66 mAh/g and the C30/Cmax of 63.65%.

关键词： hydrogen storage alloys Ti substitution structural characteristic electrochemical properties

Preparation and electrochemical properties of carbon-coated LiFePO_4 hollow nanofibers

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International Journal of Minerals,Metallurgy and Materials 2016年第4期23卷 474-480页

作者： Bin-bin Wei Yan-bo Wu Fang-yuan Yu Ya-nan Zhou College of Environmental and Chemical Engineering Dalian Jiaotong University

Carbon-coated LiFePO_4 hollow nanofibers as cathode materials for Li-ion batteries were obtained by coaxial electrospinning. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller specific surface area analysis, galvanostatic charge–discharge, and electrochemical impedance spectroscopy（EIS） were employed to investigate the crystalline structure, morphology, and electrochemical performance of the as-prepared hollow nanofibers. The results indicate that the carbon-coated LiFePO_4 hollow nanofibers have good long-term cycling performance and good rate capability： at a current density of 0.2C（1.0C = 170 mA ·g^-1） in the voltage range of 2.5–4.2 V, the cathode materials achieve an initial discharge specific capacity of 153.16 mA h·g^-1 with a first charge–discharge coulombic efficiency of more than 97%, as well as a high capacity retention of 99% after 10 cycles; moreover, the materials can retain a specific capacity of 135.68 mA h·g^-1, even at 2C.

关键词： electrospinning lithium-ion batteries carbon coatings phosphates nanofibers electrochemical properties

Effects of Al,F dual substitutions on the structure and electrochemical properties of lithium manganese oxide

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Journal of University of Science and Technology Beijing 2008年第2期15卷 182-186页

作者： Tingfeng Yi Xinguo Hu Dianlong Wang Huibin Huo School of Chemistry and Chemical Engineering Anhui University of Technology Maanshan 243002 China Department of Applied Chemistry Harbin Institute of Technology Harbin 150001 China

Spinel LiMn2O4 and F, Al-doped spinel LiAl0.05Mn1.95O3.58F0.02 have been synthesized by a soft chemistry method using adipic acid as the chelating agent. The synthesized spine/materials were characterized by differential thermal analysis （DTA） and thermogravimetery （TG）, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, cyclic voltammetry （CV）, and chargedischarge testing. The results indicate that all the samples have high phase purity, and fluorine is important in controlling the morphology; the doped aluminum enhances the stability of spinel LiMn2O4. The charge-discharge tests indicate that LiAl0.05Mn1.95O4 has high capacity retention, which is 92.60% of the initial after 50 cycles. It is found that the novel compound LiAl0.05Mn1.95O3.98F0.02 with smaller particles can offer much higher capacity, whose initial discharge capacity is 126.5 mAh·g^-1. The cyclic voltammetric experiments disclose the enhanced reversibility of the F, Al^3＋-modified spinel as compared with the undoped spinel.

关键词： lithium ion battery cathode material soft chemistry method structure electrochemical properties

Preparation, characterization and electrochemical properties of mesoporous LiFe_(0.99)Mo_(0.01)PO_4/C

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Rare Metals 2009年第4期28卷 317-321页

作者： YU Chunyang WANG Zhongli CHEN Yu XIA Dingguo CHU Wangsheng WU Ziyuc Biochemical Engineering College Beijing Union University Beijing 100023 China College of Environmental and Energy Engineering Beijing University of Technology Beijing 100022 China Beijing Synchrotron Radiation Facility Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

A mesoporous LiFe0.99Mo0.01PO4/C composite was synthesized by the sol-gel method using （NH4）2MoO4 as a doping starting material. The formation of conductive carbon, metal doping and mesopores was achieved simultaneously in the prepared material. The characterizations of crystal structures and microstructures were investigated using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, extended X-ray-absorption fine-structure （EXAFS） and X-ray-absorption near-structure spectroscopy （XANES） while the surface area was determined using N2 adsorption techniques. Cyclic voltammetry （CV） and charge-discharge cycling performance were used to characterize its electrochemical properties. The sample possessed uniformly distributed mesopores with an average pore size of 4 nm, and the specific surface area was about 69.368 m^2/g. The results show that the reversible capacity of mesoporous LiFe0.99Mo0.01PO4/C is about 160 mAh/g at 0.1C, 135 mAh/g at 1C and 90 mAh/g at 5C, respectively. The capacity fading is neglectable.

关键词： lithium ion battery cathode material mesoporous composite electrochemical properties