Energiespeichermaterialien

Die Arbeitsgruppe von Prof Riedel beschäftigt sich seit dem Jahr 2003 mit den neuesten Batteriesystemen, Li-Ionen Batterien sowie jenseits der heutigen Lithium-Ionen-Batterie. Dafür werden neue Materialien für elektrochemische Energiespeicher der nächsten und übernächsten Generation entwickelt und untersucht.

Im Fokus stehen neuartige Speichermaterialien, die als Elektroden in Lithium-Ionen-, Lithium-Natrium- und Lithium-Schwefel-Batterien sowie in Superkondensatoren eingesetzt werden können. Das Ziel im Forschungsfeld Energiespeichermaterialien ist es, neuartige Materialien mit potenziell höheren Energiedichten zu identifizieren, die gleichzeitig sicher sind und zu niedrigeren Kosten produziert werden können. Zudem soll mit diesen eine schnelle Ladung und Entladung über viele Zyklen möglich sein.

PDCs für Ionen-Batterie-Strategie

E-magy nanoporous Si-material up-scaling next generation Li ion battery anodes (ESiLiB)

Projekt im Rahmen von: EIT RawMaterials

Die Durchführung dieses zweijährigen Projekts wird zu einem verbesserten Herstellungsprozess für nanoporöses Silizium bei reduzierten Kosten, verbesserter Zirkularität und Prozessnachhaltigkeit beitragen. Die Ergebnisse dieses Projektes werden ca. 1 Jahr nach Projektende (Bauzeit für die erste maßstabsgetreue Recyclinganlage) in die Produktion übernommen.

Das Fachgebiet Disperse Feststoffe wird siliziumbasierte Anodenkonzepte testen, wobei der Fokus auf der Verbesserung der E-Magy-Materialleistung durch die Entwicklung und Optimierung einer Kohlenstoffbeschichtung liegt.

Koordination: E-magy B.V.

Partner:

Position: PhD Position, Student: Siri Gani

Im Rahmen des Projekts werden Strategien zur nachhaltigen Aufbereitung von Li-Ionen Batterien am Ende ihrerLebensdauer in Elektrofahrzeugen entwickelt.

Förderprogramm: HA Hessen Agentur GmbH, Innovationsförderung Hessen- Förderung der Elektromobilität (2020 – 2022)

Weitere Informationen und Projektbeschreibung

Projekt im Rahmen von Beethoven Classic 3, Polish-German Funding Initiative unterstützt durch Polish National Science Centre (NCN) und Deutsche Forschungsgemeinschaft (DFG), 2020-2023.

Partner:

Dr. Ing. Monika Wilamowska, Dr. Ing. Andrzej Nowak, Gdansk University of Technology (PL) and

Dr. Grzegorz Trykowski, Nicolaus Copernicus University of Torun (PL)

Weitere Informationen und Projektbeschreibung

Sodium-Ion and sodium Metal BAtteries for efficient and sustainable next-generation energy storage – (SIMBA)

Ein Konsortium unter Leitung der TU geht neue Wege zur nachhaltigen Energiespeicherung. Das Projekt „SIMBA“ strebt die Entwicklung einer sicheren, kostengünstigen und umweltschonenden Natrium-Festkörperbatterie für den stationären Einsatz an, die ein wesentliches Problem der Energiewende lösen helfen könnte.

Die EU fördert SIMBA mit acht Millionen Euro im Rahmen des „Horizon 2020“-Programms..

Weitere Informationen und Projektbeschreibung

M. Sc. Fangmu Qu

Supervisors: Ralf Riedel, Magdalena Graczyk-Zajac

Low electronic conductivity and shuttle effect of sulfur (S) hinders its application in Li-S battery [1]. Numerous carbon materials are used as host for solving above issues [2-3]. However, enough robustness for accommodating the volume expansion during cycles is not easy achieved by most of carbon materials. Porous carbon-rich SiCN/SiOC ceramic matrix is a great option for hosting S due to its robust structure stability and good electronic conductivity [4-6]. Now, we synthetized a carbon-rich SiCN ceramics with tailored morphology under different pyrolysis temperature and infiltrate sulfur into the porous ceramic matrices to form SiCN-S composites used for sulfur cathode. Then we investigated their morphology and performance. Under different pyrolysis temperature, SiCN shows different content and morphology, resulting in various electrochemical performance. SiCN ceramic pyrolyzed at 1000 ℃ exhibits best cycle stability compared with others due to it has more amorphous free carbon and nitrogen. Our work shows a new strategy for using ceramic as host material for S in Li-S battery. And in our subsequent works, we will further investigate other factors of the synthesis of SiCN-S composites on electrochemical performance as well as potential of SiOC ceramics served as sulfur host for cathode in Li-S battery.

References

[1] H.-J. Peng, J.-Q. Huang, X.-B. Cheng, Q. Zhang, Review on High-Loading and High-Energy Lithium-Sulfur Batteries, Advanced Energy Materials, 7 (2017).

[2] Y. Zhao, W. Wu, J. Li, Z. Xu, L. Guan, Encapsulating MWNTs into hollow porous carbon nanotubes: a tube-in-tube carbon nanostructure for high-performance lithium-sulfur batteries, Adv Mater, 26 (2014) 5113-5118.

[3] D. Gueon, J.T. Hwang, S.B. Yang, E. Cho, K. Sohn, D.K. Yang, J.H. Moon, Spherical Macroporous Carbon Nanotube Particles with Ultrahigh Sulfur Loading for Lithium-Sulfur Battery Cathodes, ACS Nano, 12 (2018) 226-233.

[4] J. Kaspar, M. Graczyk-Zajac, S. Choudhury, R. Riedel, Impact of the electrical conductivity on the lithium capacity of polymer-derived silicon oxycarbide (SiOC) ceramics, Electrochimica Acta, 216 (2016) 196-202.

[5] M. Graczyk-Zajac, D. Vrankovic, P. Waleska, C. Hess, P.V. Sasikumar, S. Lauterbach, H.-J. Kleebe, G.D. Sorarù, The Li-storage capacity of SiOC glasses with and without mixed silicon oxycarbide bonds, Journal of Materials Chemistry A, 6 (2018) 93-103.

[6] D. Vrankovic, M. Graczyk-Zajac, C. Kalcher, J. Rohrer, M. Becker, C. Stabler, G. Trykowski, K. Albe, R. Riedel, Highly Porous Silicon Embedded in a Ceramic Matrix: A Stable High-Capacity Electrode for Li-Ion Batteries, ACS Nano, 11 (2017) 11409-11416.

M. Sc. Mathias Storch

Supervisors: Ralf Riedel, Magdalena Graczyk-Zajac in cooperation with Mercedes-Benz AG, Kirchheim u.T.

The PhD study deals with the investigation of the degradation mechanism of lithium-ion cells aged under calendar and cycle operation. For both operation modes, a comprehensive aging test comprising 54 pouch-bag type lithium-ion cells with a capacity of 50.8 Ah (calendar) and 31 pouch-bag type lithium-ion cells with a capacity of 39 Ah (cycle) was performed for a period of ~2 years, each. Afterwards, an extensive post-mortem analysis was performed with those degraded cells. The cells were opened in argon atmosphere; the electrode materials were separated and prepared for further analysis using different material characterization methods. The methods of ICP-OES, SEM, Raman spectroscopy and XPS-depth profiling in combination with the data from electrochemical testing revealed a storage state of charge dependent growth of the solid electrolyte interphase. In the cycle aging test, the operation parameters temperature, cut-off voltage, depth of discharge, and discharge current were varied separately. In that case, the electrodes were analyzed using ICP-OES, (FIB-) SEM, XRD, STEM and XPS-depth profiling. The main degradation mechanism found are the growth of the solid electrolyte interphase, gas evolution, lithium plating, transition metal dissolution, and cathode particle cracking. In addition, inhomogeneous degradation, i.e. gas-assisted lithium plating and lithium plating resulting from thermal, current and Li- concentration gradients have been observed and formation mechanisms are proposed.

M. Sc. Nan Chai

Supervisors: Ralf Riedel, Zhaoju Yu, Magdalena Graczyk-Zajac

Polymer-derived ceramics (PDCs), including silicon oxycarbide (SiOC) and silicon carbonitride (SiCN) ceramics, have attracted much attention due to their high theoretical capacity and stability with respect to a prolonged cycling [1-2]. During charge/discharge, the major Li-ion host sites are accordingly the interstitial spaces and edges of graphene, as well as the carbon layers within the free carbon phase. Meanwhile, Carbon nanotubes (CNTs) and graphene [3-4] have also attracted much interest for their potential applications as battery material due to their excellent electrical conductivity and outstanding storage properties. Therefore, introducing CNTs and graphene into PDCs represents a highly promising approach to enhance the electrochemical performance of these materials. A chemical approach, as the drawing below shows, to blend PDCs with CNTs and graphene has already been investigated in detail. The electrochemical (EC) test have revealed high capacities of more than 600 mAh/g in line with stability over 100 cycles.

References:

[1] W. Xing, A.M. Wilson, K. Eguchi, G. Zank, J.R. Dahn, Pyrolysed polysiloxanes for use as anode materials in lithium-ion batteries, J. Electrochem. Soc. 144 (1997) 2410–2416.

[2] Wilson A M, Zank G, Eguchi K, et al. Pyrolysed silicon-containing polymers as high capacity anodes for lithium-ion batteries. Journal of Power Sources, 1997, 68(2): 195-200.

[3] Yuan, Wenyu, et al. The applications of carbon nanotubes and graphene in advanced rechargeable lithium batteries, Journal of Materials Chemistry A, 4.23 (2016): 8932-8951.

[4] Wu, Heng, et al. Graphene based architectures for electrochemical capacitors, Energy Storage Materials, 5 (2016): 8-32.