29.04.2025 by Dr. Chiara Baldini
Turning Waste Heat into Power with Nanoribbon Tech - Enhancing Performance of Thermoelectrics
In advanced materials science, precise structural engineering at the nanoscale is very important to optimize the performance of ceramic composites in various applications, including electronics, thermal management, and especially thermoelectric materials. A fundamental challenge in this field is creating controlled asymmetric structures that optimize directional properties and functional efficiency.
A recent collaborative study, "Asymmetric structuring of ceramic composite via co-electrospun sodium cobaltite and calcium cobaltite nanoribbons," published in the Journal of the American Ceramic Society, represents a significant advancement toward overcoming this challenge. Researchers from the Institute of Physical Chemistry and Electrochemistry at Leibniz University Hannover (Germany) and the Wolfson Department of Chemical Engineering at the Technion–Israel Institute of Technology (Haifa, Israel) employed an innovative fabrication method called co-electrospinning. This advanced variation of electrospinning allowed for the precise preparation of composite nanoribbons consisting of sodium cobaltite (NaCo₂O₄) and calcium cobaltite (Ca₃Co₄O₉). The approach provided accurate control over ceramic microstructure and texturing, creating materials specifically tailored for improved thermoelectric performance.
Advanced Characterization with NETZSCH DSC and LFA: Key to Thermoelectric Performance
Our laboratory at NETZSCH Analyzing & Testing contributed specialized thermal analysis essential to this research. Specifically the in-plane and out-of-plane Thermal ConductivityThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.thermal conductivity (λ) was accurately determined based on the Thermal DiffusivityThermal diffusivity (a with the unit mm2/s) is a material-specific property for characterizing unsteady heat conduction. This value describes how quickly a material reacts to a change in temperature.thermal diffusivity, measured using the NETZSCH LFA 467 HT HyperFlash, and the Specific Heat Capacity (cp)Heat capacity is a material-specific physical quantity, determined by the amount of heat supplied to specimen, divided by the resulting temperature increase. The specific heat capacity is related to a unit mass of the specimen.specific heat capacity values, obtained with the NETZSCH DSC 404 F1 Pegasus® .
These measurements contributed to a comprehensive evaluation of the composite's thermal behavior.
The study demonstrated enhanced thermoelectric performance, with a power factor of 9.9 μW/cm²K² and a ZT value of 0.49 at 1073 K, surpassing previously reported values for similar cobaltite-based materials. These improvements were linked to increased Electrical Conductivity (SBA)Electrical conductivity is a physical property indicating a material's ability to allow the transport of an electric charge.electrical conductivity enabled by optimized charge carrier properties within the nanostructured composite.
This research exemplifies how effective collaboration between academic institutions and specialized analytical laboratories can accelerate advancements in ceramic materials technology.
Acknowledgments
We gratefully acknowledge the collaborative research contributions from the Institute of Physical Chemistry and Electrochemistry at Leibniz University Hannover (Germany) and the Wolfson Department of Chemical Engineering and the Nancy & Stephan Grand Technion Energy Program (GTEP) at Technion–Israel Institute of Technology (Haifa, Israel). We are proud to have supported this study by contributing our expertise and advanced instrumentation in the field of thermal analysis.
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