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The increasing market demand and the environmental crisis have been driving the battery industry to grow faster than ever before. Modern research has been focused on new types of batteries (Li-S, Li-air, Na-air, all-solid-state lithium batteries, etc.) as well as improvement (SEI, 3D printing, etc.) of current Li-ion batteries. Due to the complexity and atmospheric sensitivity of battery systems, it has been a challenge to track the evolution of the battery components. In-situ/ex-situ synchrotron X-ray techniques (XAS, HAXPES, XES, STXM, etc.), however, have been proven to be extremely powerful tools to study these systems. In-situ/operando XAS, in particular, has the capability to track the electronic and local structures of each element during cycling. These synchrotron X-ray techniques are used to reveal the connection between the chemical structure and battery performance, and thus guide the design of novel batteries.

Related Publications:

  • Yipeng Sun, et al. A Novel Organic “Polyurea” Thin Film for Ultralong‐Life Lithium‐Metal Anodes via Molecular‐Layer Deposition. Advanced Materials 2019, 31, 4, 1806541. DOI: 10.1002/adma.201806541
  • Xuejie Gao, et al. Converting a Thick Electrode into Vertically Aligned “Thin Electrodes” By 3D-Printing for Designing Thickness Independent Li-S Cathode. Energy Storage Materials 2020, 24, 682-688. DOI: 10.1016/j.ensm.2019.08.001
  • Mohammad Banis, et al. Revealing the charge/discharge mechanism of Na-O2 cells by in situ soft X-ray absorption spectroscopy. Energy & Environmental Science 2018, 11, 2073. DOI: 10.1039/c8ee00721g
  • Bimetallic Systems

    Pt-M bimetallic systems including alloys and core-shell structures, which are studied as highly efficient electrocatalysts. By introducing a transition metal M, it is possible to tune the d-band structure of Pt, while reducing the usage of the nobel metal. This is achieved by the so-called strain effect and ligand effect, i.e., the change of the Pt valence band (providing the chemical bonds with adsorbates) due to the change of lattice/local structure. In our study, synchrotron-based X-ray techniques such as X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), and X-ray emission spectroscopy (XES) are used to investigate the electronic and local structures of each element.

    Related Publications:

  • Jiatang Chen, Y. Zou Finfrock, Zhiqiang Wang & Tsun-Kong Sham. Strain and ligand effects in Pt-Ni alloys studied by valence-to-core X-ray emission spectroscopy. Scientific Reports 2021, 11, 13698. DOI:10.1038/s41598-021-93068-0
  • Xuchun Wang, et al. The Role of Bismuth in Suppressing the CO Poisoning in Alkaline Methanol Electrooxidation: Switching the Reaction from the CO to Formate Pathway. Nano Letters 2023, 23, 2, 685–693. DOI:10.1021/acs.nanolett.2c04568
  • Jiabin Xu, et al. Atomically Dispersed Mg–N–C Material Supported Highly Crystalline Pt3Mg Nanoalloys for Efficient Oxygen Reduction Reaction The Journal of Physical Chemistry C 2023, 14, 37, 8296–8305. DOI: 10.1021/acs.jpclett.3c01870
  • Semiconductors

    1D Nano-heterostructures

    1D nano-heterostructures consisting of chemically distinct components are attracting increasing research interest because of the possibility of tuning their chemical, electronic and optical properties at a wide range, and performing multiple functionalities on single nanostructure. Motivated by these prospects, significant progress has been made regarding to the synthesis of various axial, radial, and branched nanoheterostructures via different methods, which provides a testing ground to study the fundamental effect of different components and their interface on the optical and electronic properties of nano-heterostructures. In our research, we use X-ray excited optical luminescence (XEOL) in combination with X-ray absorption near edge spectroscopy (XANES), which have unique advantages in studying the electronic structures and optical properties of semiconductor nanostructures.

    Related Publications:

  • Zhiqiang Wang, et al. Origin of luminescence from ZnO/CdS core/shell nanowire arrays Nanoscale 2014 DOI: 10.1039/C4NR02231A
  • Zhiqiang Wang, et al. 2D XANES-XEOL mapping: observation of enhanced band gap emission from ZnO nanowire arrays Nanoscale 2014,6, 6531-6536 DOI: 10.1039/c4nr01049c
  • Zhiqiang Wang, et al. Tracking the Interface of an Individual ZnS/ZnO Nano-Heterostructure Journal of Physical Chemistry C 116, 18, 10375-10381 DOI: 10.1021/jp301289x

  • 1D Nanowires and Nanotubes

    Related Publications:

  • Jun Li, et al. Revealing the Synergy of Mono/Bimetallic PdPt/TiO2 Heterostructure for Enhanced Photoresponse Performance. Journal of Physical Chemistry C 2017, 121, 24861. DOI: 10.1021/acs.jpcc.7b08144
  • Jun Li, et al. Tracking the Effect of Sodium Insertion/Extraction in Amorphous and Anatase TiO2 Nanotubes. Journal of Physical Chemistry C 2017, 121, 11773. DOI:10.1021/acs.jpcc.7b01106
  • Lu Yao, Jiatang Chen, Zhiqiang Wang, Tsun-Kong Sham. TiO2 Nanotubes: Morphology, Size, Crystallinity, and Phase-Dependent Properties from Synchrotron-Spectroscopy Studies. Journal of Physical Chemistry C 2022, 126, 6, 3265-3275. DOI: 10.1021/acs.jpcc.1c10577