Xinyao Zheng
Peking University
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Featured researches published by Xinyao Zheng.
Nano Research | 2017
Xinghua Chang; Teng Wang; Zhiliang Liu; Xinyao Zheng; Jie Zheng; Xingguo Li
We report a simple method of preparing a high performance, Sn-based anode material for lithium ion batteries (LIBs). Adding H2O2 to an aqueous solution containing Sn2+ and aniline results in simultaneous polymerization of aniline and oxidation of Sn2+ to SnO2, leading to a homogeneous composite of polyaniline and SnO2. Hydrogen thermal reduction of the above composite yields N-doped carbon with hierarchical porosity and homogeneously distributed, ultrafine Sn particles. The nanocomposite exhibits excellent performance as an anode material for lithium ion batteries, showing a high reversible specific capacity of 788 mAh·g−1 at a current density of 100 mA·g−1 after 300 cycles and very good stability up to 5,000 mA·g−1. The simple preparation method combined with the good electrochemical performance is highly promising to promote the application of Sn based anode materials.
ACS Nano | 2017
Zhiliang Liu; Xinghua Chang; Teng Wang; Wei Li; Haidong Ju; Xinyao Zheng; Xiuqi Wu; Cong Wang; Jie Zheng; Xingguo Li
Silica can be converted to silicon by magnesium reduction. Here, this classical reaction is renovated for more efficient preparation of silicon nanoparticles (nano-Si). By reducing the particle size of the starting materials, the reaction can be completed within 10 min by mechanical milling at ambient temperature. The obtained nano-Si with high surface reactivity are directly reacted with 1-pentanol to form an alkoxyl-functionalized hydrophobic colloid, which significantly simplifies the separation process and minimizes the loss of small Si particles. Nano-Si in 5 g scale can be obtained in one single batch with laboratory scale setups with very high yield of 89%. Utilizing the excellent dispersion in ethanol of the alkoxyl-functionalized nano-Si, surface carbon coating can be readily achieved by using ethanol soluble oligomeric phenolic resin as the precursor. The nano-Si after carbon coating exhibit excellent lithium storage performance comparable to the state of the art Si-based anode materials, featured for the high reversible capacity of 1756 mAh·g-1 after 500 cycles at a current density of 2.1 A·g-1. The preparation approach will effectively promote the development of nano-Si-based anode materials for lithium-ion batteries.
Advanced Materials | 2018
Xinyao Zheng; Chengkai Yang; Xinghua Chang; Teng Wang; Meng Ye; Jing Lu; Henghui Zhou; Jie Zheng; Xingguo Li
The lithium storage capacity of graphite can be significantly promoted by rare earth trihydrides (REH3 , RE = Y, La, and Gd) through a synergetic mechanism. High reversible capacity of 720 mA h g-1 after 250 cycles is achieved in YH3 -graphite nanocomposite, far exceeding the total contribution from the individual components and the effect of ball milling. Comparative study on LaH3 -graphite and GdH3 -graphite composites suggests that the enhancement factor is 3.1-3.4 Li per active H in REH3 , almost independent of the RE metal, which is evident of a hydrogen-enhanced lithium storage mechanism. Theoretical calculation suggests that the active H from REH3 can enhance the Li+ binding to the graphene layer by introducing negatively charged sites, leading to energetically favorable lithiation up to a composition Li5 C16 H instead of LiC6 for conventional graphite anode.
Nano Research | 2018
Xinghua Chang; Xinyao Zheng; Yanru Guo; Jun Chen; Jie Zheng; Xingguo Li
Magnesium hydride (MgH2) is a high-capacity anode material for lithium ion batteries, which suffers from poor cycling stability. In this study, we describe a thermal plasma-based approach to prepare homogeneous MgH2/C nanocomposites with very high cycling stability. In this process, magnesium evaporation is coupled with carbon generation from the plasma decomposition of acetylene, leading to a homogeneous Mg/C nanocomposite, which can be easily converted to MgH2/C by hydrogenation. The MgH2/C nanocomposite achieves a high reversible capacity of up to 620 mAh•g–1 after 1,000 cycles with an ultralow decay rate of only 0.0036% per cycle, which represents a significantly improved performance compared to previous results.
Journal of Materials Chemistry | 2017
Jun Chen; Jun Fu; Kai Fu; Rui Xiao; Yong Wu; Xinyao Zheng; Zhiliang Liu; Jie Zheng; Xingguo Li
The hydrogen evolution reaction (HER) during the electrochemical oxidation of borohydride is the major efficiency loss in direct borohydride fuel cells (DBFCs). Here we show that an YH2–Pd thin film electrode, which combines catalysis on the Pd layer and H storage in the YH2 layer, can effectively promote the energy utilization efficiency. The YH2 layer can absorb the atomic H generated during the BH4− oxidation on the Pd layer and effectively suppress HER. The absorbed H can be further oxidized into H2O in NaOH solution, allowing full utilization of the 8 electrons in BH4− oxidation. The YH2–Pd electrode can be regarded as a hybridization of the anodes in conventional DBFCs and nickel-metal hydride batteries. The hydrogen absorption/desorption during the electrochemical process is in situ monitored by optical transmittance measurements, which provide key insights into the interconversion mechanisms and energetics of the hydridic, neutral and protonic hydrogen species.
Journal of Materials Chemistry | 2018
Xinyao Zheng; Chengkai Yang; Xinghua Chang; Zhiliang Liu; Xiuqi Wu; Henghui Zhou; Jie Zheng; Xingguo Li
Hydrogenation of the bulk YSn2 intermetallic sample in mechanical milling yields a nanocomposite composed of Sn nanocrystals dispersed in the amorphous yttrium hydride (YHx) phase. The Sn/YHx exhibits a high volumetric lithium storage capacity of 2594 mA h cm−3 after 1000 cycles at 500 mA g−1. The hydrogenation induced phase segregation is a simple top-down approach to obtain high performance nanocrystalline Sn anode materials for lithium ion batteries.
Journal of Alloys and Compounds | 2016
Xiao Tian; Wei Wei; Ruxia Duan; Xinyao Zheng; Huaiwei Zhang; O. Tegus; Xingguo Li
Intermetallics | 2016
Huaiwei Zhang; Xinyao Zheng; Teng Wang; Xingguo Li
Electrochimica Acta | 2018
Xinghua Chang; Zhiliang Liu; Bingxue Sun; Zewei Xie; Xinyao Zheng; Jie Zheng; Xingguo Li
Materials & Design | 2017
Huaiwei Zhang; Xinyao Zheng; Teng Wang; Xingguo Li