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Dive into the research topics where Yougen Tang is active.

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Featured researches published by Yougen Tang.


Journal of Materials Chemistry | 2014

Annealed NaV3O8 nanowires with good cycling stability as a novel cathode for Na-ion batteries

Hanna He; Guanhua Jin; Haiyan Wang; Xiaobing Huang; Zehua Chen; Dan Sun; Yougen Tang

In this work, NaV3O8 nanowires are proposed as a novel cathode for a Na-ion battery for the first time. The as-prepared nanowires are characterized well by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, thermogravimetry (TG), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Sodium insertion/extraction properties of as-prepared nanowires with or without thermal treatment are compared. It is found that thermal treatment could remove some crystal water in the host, resulting in a contracted crystal volume. In comparison with the untreated sample, although the reversible discharge capacity of annealed NaV3O8·xH2O nanowires is decreased from 169.6 mA h g−1 to 145.8 mA h g−1 when cycled at 10 mA g−1, it shows good capacity retention of ca. 91.1% after 50 cycles, much higher than that (51.9%) of the untreated sample. Annealed NaV3O8 nanowires exhibit much better cycling stability and charge–discharge plateaus during the Na-ion insertion/extraction processes, which should be attributed to the contracted crystal volume and the increased crystallinity.


Journal of Materials Chemistry | 2014

Aqueous rechargeable lithium batteries using NaV6O15 nanoflakes as high performance anodes

Dan Sun; Guanhua Jin; Haiyan Wang; Ping Liu; Yu Ren; Yifan Jiang; Yougen Tang; Xiaobing Huang

Poor cycling performance is still the big challenge for aqueous rechargeable lithium batteries (ARLBs), in which the instability of the anode is considered to be the main issue. In this work, NaV6O15 nanoflakes were synthesized by a two-step approach and a NaV6O15//LiMn2O4 ARLB system with superior cycling performance was constructed. The galvanostatic charge–discharge result demonstrates an initial discharge capacity of 110.7 mA h g−1 (based on anode mass) at 150 mA g−1 and the capacity retention of ca. 90% and 80% at 300 mA g−1 after 100 and 400 cycles, respectively. Such superior cycling performance of ARLBs is mainly due to the intrinsic 3-D tunneled structure of NaV6O15, nanoflake morphology and relatively stable electrode surface, as verified by the X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) results of the tested electrodes. Moreover, a simple single-phase reaction mechanism during the lithium ion insertion/extraction process is observed for NaV6O15 by XRD analysis.


ACS Applied Materials & Interfaces | 2017

Tuning the Morphologies of MnO/C Hybrids by Space Constraint Assembly of Mn-MOFs for High Performance Li Ion Batteries

Dan Sun; Yougen Tang; Delai Ye; Jun Yan; Haoshen Zhou; Haiyan Wang

Morphology controllable fabrication of electrode materials is of great significance but is still a major challenge for constructing advanced Li ion batteries. Herein, we propose a novel space constraint assembly approach to tune the morphology of Mn(terephthalic acid) (PTA)-MOF, in which benzonic acid was employed as a modulator to adjust the available MOF assembly directions. As a result, Mn(PTA)-MOFs with microquadrangulars, microflakes, and spindle-like microrods morphologies have been achieved. MnO/C hybrids with preserved morphologies were further obtained by self-sacrificial and thermal transformation of Mn(PTA)-MOFs. As anodes for Li ion batteries, these morphologies showed great influence on the electrochemical properties. Owing to the abundant porous structure and unique architecture, the MnO/C spindle-like microrods demonstrated superior electrochemical properties with a high reversible capacity of 1165 mAh g-1 at 0.3 A g-1, excellent rate capability of 580 mAh g-1 at 3 A g-1, and no considerable capacity loss after 200 cycles at 1 A g-1. This strategy could be extended to engineering the morphology of other MOF-derived functional materials in various structure-dependent applications.


ACS Applied Materials & Interfaces | 2015

High-Rate LiTi2(PO4)3@N-C Composite via Bi-nitrogen Sources Doping.

Dan Sun; Xia Xue; Yougen Tang; Yan Jing; Bin Huang; Yu Ren; Yan Yao; Haiyan Wang; Guozhong Cao

Mesoporous LiTi2(PO4)3@nitrogen-rich doped carbon composites have been synthesized by a novel bi-nitrogen sources doping strategy. Tripolycyanamide (C3H6N6) and urea are proposed for the first time as both nitrogen and carbon sources to achieve a homogeneous nitrogen-doped carbon coating layer via an in situ method. The electrode delivers ultrahigh rate performance and outstanding cycling stability in lithium ion batteries (LIBs). In an organic electrolyte system, the electrode demonstrates high discharge capacities of 120 mAh g(-1) and 87 mAh g(-1) at 20C and 50C, respectively. Moreover, 89.5% of initial discharge capacity is retained after 1000 cycles at 10C. When used as an anode for aqueous LIBs, the electrode also demonstrates superior rate capability with the discharge capacity of 103 mAh g(-1) at 10C, corresponding to 84% of that at 1C. Outstanding cycling stability with capacity retention of 91.2% after 100 cycles at 30 mA g(-1) and 90.4% over 400 cycles at 150 mA g(-1) are also demonstrated. The uniform nitrogen-rich carbon coating and unique mesoporous structure play important roles in effectively suppressing the charge-transfer resistance and facilitating Li ion/electron diffusion, thus leading to the superior electrochemical properties.


Scientific Reports | 2015

Advanced aqueous rechargeable lithium battery using nanoparticulate LiTi2(PO4)3/C as a superior anode

Dan Sun; Yifan Jiang; Haiyan Wang; Yan Yao; Guoqing Xu; Kejian He; Suqin Liu; Yougen Tang; Younian Liu; Xiaobing Huang

Poor cycling performance arising from the instability of anode is still a main challenge for aqueous rechargeable lithium batteries (ARLB). In the present work, a high performance LiTi2(PO4)3/C composite has been achieved by a novel and facile preparation method associated with an in-situ carbon coating approach. The LiTi2(PO4)3/C nanoparticles show high purity and the carbon layer is very uniform. When used as an anode material, the ARLB of LiTi2(PO4)3/C//LiMn2O4 delivered superior cycling stability with a capacity retention of 90% after 300 cycles at 30 mA g−1 and 84% at 150 mA g−1 over 1300 cycles. It also demonstrated excellent rate capability with reversible discharge capacities of 115 and 89 mAh g−1 (based on the mass of anode) at 15 and 1500 mA g−1, respectively. The superior electrochemical properties should be mainly ascribed to the high performance of LiTi2(PO4)3/C anode, benefiting from its nanostructure, high-quality carbon coating, appropriate crystal structure and excellent electrode surface stability as verified by Raman spectra, electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements.


ACS Applied Materials & Interfaces | 2017

Iron-Doped Cauliflower-Like Rutile TiO2 with Superior Sodium Storage Properties

Hanna He; Dan Sun; Qi Zhang; Fang Fu; Yougen Tang; Jun Guo; Minhua Shao; Haiyan Wang

Developing advanced anodes for sodium ion batteries is still challenging. In this work, Fe-doped three-dimensional (3D) cauliflower-like rutile TiO2 was successfully synthesized by a facile hydrolysis method followed by a low-temperature annealing process. The influence of Fe content on the structure, morphology, and electrochemical performance was systematically investigated. When utilized as a sodium ion battery anode, 6.99%-Fe-doped TiO2 exhibited the best electrochemical performance. This sample delivered a very high reversible capacity (327.1 mAh g-1 at 16.8 mA g-1) and superior rate performance (160.5 mAh g-1 at 840 mA g-1), as well as long-term cycling stability (no capacity fading at 1680 mA g-1 over 3000 cycles). Density functional theory (DFT) calculations combined with experimental results indicated that the significantly improved sodium storage ability of the Fe-doped sample should be mainly due to the increased oxygen vacancies, narrowed band gap, and lowered sodiation energy barrier, which enabled much higher electronic/ionic conductivities and more favorable sodium ion intercalation into rutile TiO2.


RSC Advances | 2015

Large-scale fabrication of porous carbon-decorated iron oxide microcuboids from Fe–MOF as high-performance anode materials for lithium-ion batteries

Minchan Li; Wenxi Wang; Mingyang Yang; Fucong Lv; Lujie Cao; Yougen Tang; Rong Sun; Zhouguang Lu

A facile, cost-effective and environmentally friendly route has been developed to synthesise porous carbon-decorated iron oxides on a large scale via annealing iron metal–organic framework (MOF) precursors. The as-prepared C–Fe3O4 particles exhibit microcuboid-like morphologies that are actually composed of ultrafine nanoparticles and show a greatly enhanced lithium storage performance with high specific capacity, excellent cycling stability and good rate capability. The C–Fe3O4 electrodes demonstrate a high reversible capacity of 975 mA h g−1 after 50 cycles at a current density of 100 mA g−1 and a remarkable rate performance, with capacities of 1124, 1042, 886 and 695 mA h g−1 at current densities of 100, 200, 500 and 1000 mA g−1, respectively. The satisfactory electrochemical performance was attributed to the hierarchical architecture, which benefitted from the synergistic effects of the high conductivity of the carbon matrix, the cuboid-like secondary particles on the microscale, and the ultrafine primary nanoparticles on the nanoscale. This low-cost and simple method provides the possibility to prepare anode materials on a large scale and hence may have great potential applications in energy storage and conversion.


Transactions of Nonferrous Metals Society of China | 2010

Photocatalytic activity of CuO towards HER in catalyst from oxalic acid solution under simulated sunlight irradiation

Mao-hai Yao; Yougen Tang; Li Zhang; Haihua Yang; Jian-hui Yan

CuO was synthesized by thermal decomposition of Cu(NO3)2·3H2O at various temperatures and characterized by powder X-ray diffractometry (XRD) as well as scanning electron microscopy (SEM). The effects of calcination temperature, category of sacrificial reagent, initial sacrificial reagent concentration, and Ag loading content on the photocatalytic activity of the as-obtained CuO sample were investigated. The results show that the as-obtained CuO exhibits high activity for photocatalysis of H2 evolution reaction (HER) in oxalic acid solution under simulated sunlight irradiation. The highest photocatalytic activity of the as-obtained CuO was achieved at the calcination temperature of 1 000 °C, and oxalic acid was used as the sacrificial reagent with the concentration 0.05 mol/L. H2 evolution rate is as high as 2.98 mmol/(h·g) with 2% (mass fraction) loaded Ag. The possible photocatalytic reaction mechanism on the CuO photocatalyst for HER in oxalic acid solution was also discussed.


Scientific Reports | 2015

Long-lived Aqueous Rechargeable Lithium Batteries Using Mesoporous LiTi2(PO4)3@C Anode.

Dan Sun; Yougen Tang; Kejian He; Yu Ren; Suqin Liu; Haiyan Wang

The instability of anode materials during cycling has been greatly limiting the lifetime of aqueous rechargeable lithium batteries (ARLBs). Here, to tackle this issue, mesoporous LiTi2(PO4)3@C composites with a pore size of 4 nm and a large BET surface area of 165 m2 g−1 have been synthesized by a novel two-step approach. The ARLB with this type of LiTi2(PO4)3@C anode, commercial LiMn2O4 cathode and 2 M Li2(SO4) aqueous solution (oxygen was removed) exhibited superior cycling stability (a capacity retention of 88.9% after 1200 cycles at 150 mA g−1 and 82.7% over 5500 cycles at 750 mA g−1) and excellent rate capability (discharge capacities of 121, 110, 90, and 80 mAh g−1 based on the mass of LiTi2(PO4)3 at 30, 150, 1500, and 3000 mA g−1, respectively). As verified, the mesoporous structure, large surface area and high-quality carbon coating layer of the LiTi2(PO4)3@C composite contribute to the breakthrough in achieving excellent electrochemical properties for ARLB.


Journal of Materials Chemistry | 2014

LixV2O5/LiV3O8 nanoflakes with significantly improved electrochemical performance for Li-ion batteries

Dan Sun; Guanhua Jin; Haiyan Wang; Xiaobing Huang; Yu Ren; Jiecao Jiang; Hanna He; Yougen Tang

Poor cycling stability and rate capability are the main challenges for LiV3O8 as the cathode material for Li-ion batteries. Here a novel strategy involving the self-transformation of superficial LiV3O8 in a reducing atmosphere (H2–Ar) was reported to fabricate LixV2O5/LiV3O8 nanoflakes. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM) results demonstrate that LixV2O5/LiV3O8 nanoflakes could be in situ formed and that the thickness of the LixV2O5 layer is controllable. When used as a cathode for a Li-ion battery, the LixV2O5/LiV3O8 nanoflakes exhibit significantly improved cycling stability with a capacity retention of ca. 82% over 420 cycles at a 1 C-rate (1 C = 300 mA g−1), and much better rate performance compared with bare LiV3O8. The improvement of the electrochemical performance could be attributed to the unique core–shell structure, in which the ultrathin LixV2O5 layer could not only protect the internal LiV3O8 from dissolution, but also increase the Li ion diffusion coefficient and suppress the charge-transfer resistance, as verified by electrochemical impedance spectroscopy (EIS) and XRD results.

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Haiyan Wang

Central South University

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Zhouguang Lu

University of Science and Technology

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Dan Sun

Central South University

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Xiaobing Huang

Hunan University of Arts and Science

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Jingsha Li

Central South University

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Hanna He

Central South University

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Zhiguang Peng

Central South University

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Guanhua Jin

Central South University

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Jiajie Chen

Central South University

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Kun Liu

Central South University

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