Highly Integrated Systems for THz-boosted NMR identification of dendrite formation in Lithium and Sodium Batteries

• Applicants: Professor Dr. Jens Anders; Professor Dr. Klaus Lips
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering ; Communication Technology and Networks, High-Frequency Technology and Photonic Systems, Signal Processing and Machine Learning for Information Technology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 469042906

The proposed project will pioneer the use of chip-integrated THz sources, previously exclusively used for electron paramagnetic resonance-on-a-chip (EPRoC) measurements in the first funding phase of the priority program, in battery research, enhancing nuclear magnetic resonance (NMR) sensitivity to dendritic microstructures on lithium metal surfaces during charge/discharge cycles through dynamic nuclear polarization (DNP). The use of lithium metal anodes is a sought-after goal in battery development, as it offers significant advantages in terms of energy density and voltage. However, its reactive surface decreases cycle life and may cause short circuits due to the formation of lithium dendrites and other microstructures on the metal anode surface, the development of which is still poorly understood due to the lack of spectroscopic methods that would enable in-operando measurements, as well as the poor intrinsic sensitivity of NMR. By leveraging intact batteries and DNP through THz magnetic fields generated by EPRoC technology, this project aims to understand the processes leading to dendrite formation, offering insights crucial for battery stability and performance. Moreover, the project anticipates extending EPRoC's application to post-lithium technologies, such as sodium metal, opening avenues for broader battery research applications. To achieve these goals, significant improvements beyond the current state-of-the-art in the EPRoC technology are needed. More specifically, the proposed project aims to enable pulsed DNP schemes and extend the working frequencies beyond 263 GHz through novel circuit topologies. These performance improvements will be accompanied by an increase in the power efficiency of the integrated system to allow for low-temperature operation down to cryogenic temperatures. Moreover, we will investigate the use of higher harmonic frequencies of the used oscillator circuits, including boosting the higher harmonic frequencies, aiming at reaching frequencies as high as 1.2 THz. To enable the THz fields to penetrate the metallic electrode of the battery, we will explore both conventional metal mesh electrodes as well as plasmonic metasurfaces that could locally enhance the needed magnetic component of the THz field.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2314: INtegrated TERahErtz sySTems Enabling Novel Functionality (INTEREST)