First virtual Bilateral Conference on Functional Materials (BiC-FM). Сборник статей

J¹., Wester N¹., Etula J¹., Mynttinen E²., Laurila T².

      ¹Aalto University, School of Chemical Engineering, Espoo, Finland

      ²Aalto University, School of Electrical Engineering, Espoo, Finland

      [email protected]

      Bio-sensing by applying electrochemical measurements offers several benefits in development of fast and simple devices. They have been investigated for detection of neural transmitters (e.g. dopamine) and recently for detection of drug molecules in blood samples. In this presentation the development of electrode materials made of thin amorphous carbon films and single wall carbon nanotube networks are reported. Layered structures prototype thin film sensors applying perm selective nafion top coatings are also demonstrated. Sensitivity and selectivity for bio-molecules detection in physiologically relevant concentrations has been demonstrated for analytes such as opioids and other analgesics together with most relevant interfering molecules.

      Acknowledgement.This work was supported by Business Finland (FEDOC 211637 and FEPOD 2117731 projects), Aalto CHEM Doctoral School and Orion Research Foundation Sr for funding. The authors acknowledge the provision of facilities by Aalto University OtaNano−Micronova Nanofabrication Center and Aalto University Raw materials Infrastructure.

      Prof. Jari Koskinen is professor of Materials Science at Aalto University, School Chemical Engineering. He has an experience of over 35 years in the field of surface engineering and in particular on development of carbon nanomaterials and coatings. He has over 180 international publications of the topic. He is leading a research group: “Physical properties surfaces and interfaces”. The main impact of his research in material science are in the field of tribology and currently in electrochemical bio-sensing. Currently he is head of the Department of Chemistry and Materials Science. His H-index is 28.

      Defects in olivine-type cathode materials for Li-ion batteries

      Trussov I. A.¹, Nazarov E. E.¹, Aksyonov D. A.¹, Fedotov S. S.¹

      1 – Skolkovo Institute of Science and Technology, Moscow, Russia

      [email protected]

      LiFePO₄ is a commercialized cathode material ensuring wide applications of Li-ion battery technology for stationary energy storage and renewable energy sources. Regardless of the obvious simplicity of its crystal structure and chemical composition, LiFePO₄ holds astonishing defects chemistry arising from the rearrangement of cations and vacancies within tetrahedral and octahedral sites, variations in their occupancies and iron oxidation state. It was demonstrated that so-called “Li-rich” phases might form with the Li excess being located at the Fe sites reaching up to 10 %. At the same time the polyanion sublattice was rarely considered defective. It was taken for granted that the PO₄ group is highly durable, with no defects being possible at the P site.

      In this talk, we will concentrate upon various old and new defect peculiarities in LiFePO₄ and its Li-rich counterpart studied by combined X-ray and neutron diffraction methods coupled with high-throughput DFT and MD calculations. The recently discovered cations arrangements and off-stoichiometry in LiFePO₄ due to a partial replacement of Fe with Li atoms or PO₄ with hydroxyl groups for hydrothermally prepared samples at different synthesis conditions will be discussed. Such off-stoichiometries can reach over 10 % yielding Li_1+xFe_1-xPO₄ (x ≤ 0.1) and Li_1-xFe_1+x(PO₄)_1-y(OH)_4y (x ≤ 0.05, y ≤ 0.1) solid solutions respectively. Both Li and OH-substitutions trigger essential changes in the crystal structure and properties, increasing the migration barriers for Li ions and affect the electrochemical performance. We demonstrated that the off-stoichiometry significantly depends on the precursors and reducing agent concentrations and the order of mixing thereof, rendering them critical parameters that control the defects formation of the hydrothermally synthesized LiFePO₄-based cathode materials.

      More data on the crystal structure and properties of Li-rich LiFePO₄ and OH-substituted LiFePO₄ as well as the interrelation between “new” and “old” defects in synthetic phosphates and natural olivine-type minerals will be presented and analyzed.

      Acknowledgement.This work was supported by the Russian Foundation for Basic Research, grant 18-29-12097.

      Ceramic fuel cell fabrication trend from conventional methods to digital printing

      Muhammad Imran Asghar^1,2, Peter D. Lund¹

      New Energy Technologies Group, Department of Applied Physics, Aalto University School of Science, P. O. Box 15100, FI-00076 Aalto, Espoo, Finland.

      Faculty of Physics and Electronic Science, Hubei University, Wuhan, Hubei, 430062, China.

      [email protected]

      Ceramic fuel cell, a.k.a. solid oxide fuel cell, has been emerging as a clean energy technology [1–3]. Researchers of the fuel cell community have been reporting promising electrode and electrolyte materials for the fuel cell since many decades. Many researchers reported fabrication of their cells using power-press methods [4,5]. Although this method is good for the small-scale research studies, this method is not suitable for large-scale upscaling of the technology. The current state-of-the-art ceramic fuel cells are manufactured using tape-casting and screen-printing techniques. Other techniques such as pulse laser deposition, spraying techniques, atomic layer deposition, physical and chemical vapor deposition methods, have been reported as well. Recently, the fabrication of ceramic fuel cell fabrication have been reported using ink-jet and 3D printing techniques. These low-cost printing techniques could solve many issues faced by the promising fuel cell technology. In this study, an overview on the trend of the ceramic fuel cell fabrication and their effects on the cell performance and stability will be presented. The key challenges related to the conventional and 3D fabrication will be highlighted in the work.

      Figure 1: up) Traditional 3-layer ceramic nanocomposite fuel cell; down) so called “single-layer” ceramic fuel cell.

      Acknowledgement.This work is supported by Academy of Finland (Grant No. 13329016). Dr. Asghar thanks Academy of Finland (Grant No. 13322738) and the Hubei overseas Talent 100 program for their support.

      References

      [1] M. I. Asghar, M. Heikkilä and P. D. Lund, Materials Today Energy, 5 (2017) 338.

      [2] M. I. Asghar, S. Jouttijärvi and P. D. Lund, International Journal of Hydrogen energy, 43 (2018) 12892.

      [3] M. I. Asghar, S. Jouttijärvi and P. D. Lund, International Journal of Hydrogen energy, 43 (2018) 12797.

      [4] M. I. Asghar, S. Jouttijärvi, R. Jokiranta, A. Valtavirta and P. D. Lund, Nanoenergy, 53 (2018) 391.

      [5] M. I. Asghar, S. Jouttijärvi, R. Jokiranta, E. Hochreiner and P. D. Lund, International Journal of Hydrogen Energy, (2019).

      Friday, October 9

      Oral Sessions

      Day 2, Octorber 9

      Session 4: Photonics of functional materials I Chairs: N. Gippius/ D. Kopylova

      10.00–10.25

      Keynote Talk 9 Prof. Zhipei Sun

      Nonlinear Optics with Nanomaterials

      10.25–10.50

      Keynote Talk 10 Dr. Yury Gladush

      Aerosol synthesized carbon nanotube thin