Physics

Dr. Venkateswarlu Daramalla
ETH Zurich

Abstract:

Complex metal oxides-based materials and devices based on their nanostructurd thin films & heterostructures provide a plethora of applications and are considered as promising next-generation devices. Among them, titanium niobium oxide (TNO) materials found growing interest due to their complex disorder layered structures which offer unique functional properties. Nonetheless, the synthesis (growth) of quality titanium niobium oxide thin films is not realized until recently. The fundamental understanding and growth of these exotic complex oxide systems could lead to the development of next generation high energy storage & conversion systems like solid-state batteries, photoanodes, and transparent oxide electronics devices.

Towards this, we have been developing TiNb₂O₇ oxides in thin film form using physical vapor deposition methods for the first time and successfully demonstrated their usage as negative electrodes in rechargeable Li-ion thin film (micro) batteries. Moreover, the amorphous of TNO thin films also offering superior energy storage properties over their crystalline TNO and commercial Li₄Ti₅O₁₂ (LTO) negative electrodes, with remarkable high initial discharging capacity ≈ 226 μAh/μm¹cm² (≈ 460 mAh/g) at 17 μA /cm² current density, excellent coulombic efficiency (> 99%), reversible kinetics and stable crystal structures in the operating voltage window of 0.1−3.0 V.  This research opened up a new research paradigm for developing novel solid-state thin film (micro) batteries, coupled with suitable electrodes (for ex. Li-metal based solid state batteries) and solid oxide electrolyte materials; thus, very much promising for powering next generation CMOS, integrating with RFID, portable-wearable technology and IoT sensors applications. In my talk, I will discuss the important concepts of all solid-state thin film batteries using our research findings and discuss challenges that need to be addressed further.

References:

[1] J.T. Han, Y.H. Huang, and J.B. Goodenough., Chem. Mater. 23,2027 (2011)

[2] V. Daramalla and S.B.Krupandihi., MRS Proceedings 1805, mrss15-2128679 (2015)

[3] V. Daramalla, Tirupathi Rao Penki, N Munichandraiah, and S. B. Krupanidhi., Materials Science & Engineering. B, 213, 90–97 (2016)

[4] V. Daramalla, G Venkatesh, B Kishore, N Munichandraiah, SB Krupanidhi, Journal of Electrochemical Society, 165 (5), A764–A772 (2018).

[5] V. Daramalla*, S. Dutta*, S. B. Krupanidhi, Journal of European Ceramic Society (2019), accepted

[6] V. Daramalla, S. B. Krupanidhi, Thin Solid Films (2019), under revision

[7] E. Burns, D. Pergolesi, Thomas J. Schmidt, T. Lippert, and V. Daramalla, submitted 2019(under review)