| RESEARCH HIGHLIGHTS |


many types of follicular helper T cells from blood and tonsils. Plus, says Chen, “we have tested the utility of cytofkit on a large number of other datasets not mentioned in the paper.” Cytofkit is also gaining popularity with scientists around the world. “It now has


more than 4,000 users,” says Chen. Her lab continues to improve and upgrade the tool in response to user feedback. The software — which works both


on flow and mass spectrometry datasets alike — is freely available through


Bioconductor, an open-source software framework for biologists.


1. Chen, H., Lau, M. C., Wong, M. T., Newell, E. W., Poidinger, M. & Chen, J. A bioconductor package for an integrated mass cytometry data analysis pipeline. PLOS Computational Biology 12, e1005112 (2016).


Electrochemistry


GOING CARBON FREE BOOSTS BATTERY LIFE


DROPPING THE CARBON FROM A KEY BATTERY COMPONENT COULD FINALLY ENABLE LONG-LIFE, LOW-COST GRID- CONNECTED BATTERIES FOR RENEWABLE ENERGY STORAGE


Zinc–air batteries are one of the most promising solutions for the large-scale storage of intermit- tently generated renewable electricity from solar, wind or tidal: they are non-flammable and inexpensive and have a very high energy density.


But the lifetime of current zinc–air devices


is far too short to be commercially viable, because oxygen attacks and corrodes their carbon-based components. Researchers at A*STAR have now developed a carbon-free version of one of the battery’s key components, the oxygen electrocatalyst1. Conventional rechargeable batteries store


Oxygen (red) and water (red and blue) molecules react on the carbon-free electrocatalyst surface (gray) as the metal-air battery is charged.


www.astar-research.com


all electrochemically active materials within the device. Metal–air batteries, however, use oxygen from the surrounding air as the active cathode material, significantly boosting the battery’s storage capacity. To incorporate oxygen into the battery’s electrochemical cycle, these batteries use an oxygen electrocatalyst, which requires good electrical conductivity for fast electron transfer. Various metals and other catalytic materials have been tried as the electrocatalyst, but virtually all have to be laced with carbon to raise their electrical conductivity. Over time, the carbon corrodes, eventually leading to device failure. Yun Zong and Zhaolin Liu from the Insti- tute of Materials Research and Engineering


(IMRE) at A*STAR and their colleagues have now developed a highly active oxygen electro- catalyst that contains no carbon. This material — nickel-doped lanthanum


strontium manganite (LSMN) — is a member of the perovskite family, a recently discovered group of electrochemically active materials that are also causing a stir as potential solar panel materials. “The high intrinsic electrical conductivity of LSMN means that carbon is not needed as additive for conductivity enhancement,” Zong says. By alternating the ratio of nickel to manga-


nese in the material, Zong was able to tune the perovskite’s performance. The best-performing formulation, containing 10 per cent nickel, matched the electrocatalytic performance of palladium on carbon, the current benchmark electrocatalyst. Yet without the carbon, the stability of the material was greatly enhanced. The team tested LSMN over 300 electrochem- ical cycles and saw negligible performance degradation. The next hurdle to overcome, Zong


explains, is changing the process. In current metal–air battery designs, the catalyst is formed layer by layer on to a mat of carbon. “This defeats the purpose of using carbon-free catalysts, as underlying carbon may still suffer corrosion,” Zong says. One possibility is to replace the carbon mats with a nickel foam, on to which the carbon-free electrocatalyst could be grown in situ, he adds. “Our group is developing metal-air batteries where all components are essentially carbon free.” The team is also working on carbon-free


versions of other battery technologies, says Zong.


1. Ge, X., Du, Y., Li, B., Hor, T. S. A., Sindoro, M. et al. Intrinsically conductive perovskite oxides with enhanced stability and electrocatalytic activity for oxygen reduction reactions. ACS Catalysis 6, 7865−7871 (2016).


A*STAR RESEARCH 37


© 2017 A*STAR Institute of Materials Research and Engineering


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56