With the world grappling with a wide  range of issues around energy supply and use, a group of  interdisciplinary scholars from Southern University of Science and  Technology (SUSTech) has made new findings in three distinct areas of  material science.

    Chair Professor Hsing-Lin Wang (Materials Science and Engineering) has led his research group to publish cutting-edge papers in high-impact academic journals, Nano Energy (IF = 15.548), ACS Nano (IF = 13.903), and Journal of the American Chemical Society (IF = 14.695), also known as JACS.

    The paper published in Nano Energy was titled, “Single Fe atoms anchored by short-range ordered nanographene boost oxygen reduction reaction in acidic media.” The article sought to develop efficient and stable non-platinum-based (Pt) electrocatalysts.

    These electrocatalysts play a vital role in clean energy conversion  devices, and generating them at a commercial scale is of critical  importance. The primary focus of the paper was to find an alternative to  the scarce and expensive Pt, ideally using a metal that is cheap and  abundant throughout the world.

Figure 1. The Cs-TEM image of the single-atom catalysts for oxygen reduced reaction in acidic media.

    The research team synthesized single iron (Fe) atoms within a nitrogen-doped nanographene (Fe₁-N-NG).  It was loaded on to a reduced graphene oxide (RGO) structure to create a  highly efficient electrocatalyst with a well-defined structure. The use  of this architecture, known as nanographene, allowed the scholars to  precisely control its atomic structure during organic synthesis.

    The researchers found that the half-wave potential of the Fe₁-N-NG/RGO  electrocatalyst was 0.84 V, just 20 mV (2.38%) of commercial Pt/C  catalysts. Their newly-created electrocatalyst was highly stable, with  the half-wave potential changing by no more than 5 mV over fifteen  thousand cycles.

    Their findings offer significant opportunities for further research  into proton exchange membrane fuel cells (PEMFCs) as a sustainable  energy conversion technology.

    The co-first authors of the paper are SUSTech postdoctoral researcher Shaoqing Chen and Nianji Zhang. The research team of Chair Professor Hsing-lin Wang collaborated with Associate Professor Hu Xu (SUSTech Department of Physics), whose team created a theoretical model for simulating the electrocatalytic reaction process.

    Additional support came from the Los Alamos National Laboratory, the State Key Lab of Inorganic Synthesis and Preparative Chemistry (Jilin University), the Hefei National Laboratory for Physical Sciences at the Microscale (University of Science and Technology of China), and the State University of New York (Buffalo).

    The research received funding support from the Leading Talents of  Guangdong Province Program, the Shenzhen Basic Research Fund, and the  National Key Research and Development Program of China.

    Article link: https://www.sciencedirect.com/science/article/abs/pii/S2211285519308717

    The paper published in ACS Nano was titled, “C₆₀(OH)₁₂ and Its Nanocomposite for High-Performance Lithium Storage.” This article examined the use of organic carbon materials for improving lithium-ion batteries.

    The use of rechargeable lithium-ion batteries (LiBs), as an energy  storage device, has been widely used in technologies, ranging from  portable electronics to electric vehicles

    The energy densities of current commercialized batteries do not meet  the demands of consumers. Enhancing the capacity of the anode in the  LIBs by reducing the weight of anode electrodes is one alternative to  improving the energy density of batteries.

    The majority of research in this field had previously focused on  inorganic materials, which lack the long-term capacity during charging  and discharging. With that in mind, the researchers used C₆₀(OH)₁₂ and graphene oxide (GO) as the raw materials to create a high-performance anode nanocomposite for lithium storage.

Figure 2. High-performance lithium storage materials based on C60 Derivative and graphene oxide composite.

    The research team was able to show a significantly higher reversible cycling capacity than either C₆₀(OH)₁₂ and GO alone. The improved electrochemical performance can be attributed to the distribution of C₆₀(OH)₁₂ between GO layers. The electrochemical performance is also improved through the rapid cycling of lithium ions (Li⁺), and the larger number of oxygen groups also support improved performance.

    The co-first authors of the paper are SUSTech graduate student Zhengang Li and National Taiwan University (NTU) Dr. Shih-Hao Wang. The correspondent authors were SUSTech Hsing-Lin Wang and NTU Professor Leeyih Wang. Other supporting institutions were the Harbin Institute of Technology and Northeast Normal University.

    The teams received support from the Leading Talents of Guangdong  Province Program, the Key-Area Research and Development Program of  Guangdong Province, the Shenzhen Basic Research Fund, the National Key  Research and Development Fund of China, the Guangdong Provincial Key  Laboratory of Energy Materials for Electric Power, and the Shenzhen Key  Laboratory Project. The team sincerely thanks the Center of Atomic  Initiative for New Materials (NTU) and the Ministry of Science and  Technology (MOST) for their financial support, as well as the Instrument  Center at NTU for their technical support.

    Article link: https://pubs.acs.org/doi/10.1021/acsnano.9b06791

    The paper published in JACS was titled, “Evidence of Ferroelectricity of All-Inorganic Perovskite CsPbBr₃ Quantum Dots.”  Quantum dots offer enormous potential across a vast array of fields,  but little research has been conducted into their ferroelectric  properties. Ferroelectricity is a physical property of certain materials  where they show an electric polarization depending on the application  of an external electric field.

Figure 3. Ferroelectric properties of all inorganic halide perovskite CsPbBr₃ quantum dots

    The researchers discovered, for the first time, that an inorganic halide perovskite made up of cesium, lead, and bromine (CsPbBr₃).  They synthesized it into a quantum dot and were able to show a  reversible phase change between 263 K and 298 K. Their further testing  showed that they could combine the ferroelectric and optoelectric  properties in quantum dots for further interdisciplinary research. It  opens up new horizons to explore high-performing multifunctional  materials.

    The first author of the paper is doctoral candidate Xia Li. The  correspondent authors are SUSTech Chair Professor Hsing-Lin Wang and Jilin University Professor Hongming Yuan. Other contributing researchers were from Southern University of Science and Technology (SUSTech), State Key Lab of Inorganic Synthesis and Preparative Chemistry (Jilin University), the Institute of High Energy Physics, and the Spallation Neutron Source Science Center.

    Article link: https://pubs.acs.org/doi/abs/10.1021/jacs.9b12254