PhD position - Photothermal Investigations of Thermal Transport in Phase-Change Nanocomposites for Energy Storage Systems

Scientific Context and Objectives

Thermal energy storage (TES) is a key enabling technology for the large-scale integration of renewable energy sources into heating and cooling systems. Among TES solutions, phase-change materials (PCMs), such as n-alkanes, are particularly attractive due to their high latent heat capacity and tunable phase-transition temperatures. However, their intrinsically low thermal conductivity severely limits heat-charging and discharging rates, reducing the overall efficiency of thermal storage devices.

Fig. 1. Schematic setup of the temperature chamber for the photoacoustic characterization of the thermal properties of PCM-based nanocomposite systems

A promising strategy to overcome this limitation is to embed PCMs within nanostructured solid matrices, such as porous silicon, thereby forming solid–liquid nanocomposites. While such systems often exhibit improved effective thermal properties, their thermal transport behavior, especially near the phase-change temperature, remains poorly understood. In this regime, heat diffusion, latent heat effects, and interfacial phenomena are strongly coupled, and conventional contact-based thermal measurement techniques often fail due to system perturbation and spatial heterogeneity. The objective of this PhD project is to develop and apply non-contact photothermal and photoacoustic techniquesfor the quantitative characterization of thermal transport in PCM-based nanocomposites, with a particular focus on the solid–liquid phase-transition regime. The project aims to extract effective thermal diffusivity and thermal conductivity across the phase change and to establish clear correlations between confinement effects, phase-change behavior, and macroscopic thermal performance.

Research Approach

Model systems will consist of porous silicon matrices infiltrated with n-alkane PCMs (e.g. hexadecane). Phase-change properties, including latent heat, transition temperatures, and thermal hysteresis, will be investigated using Differential Scanning Calorimetry (DSC), complemented by Raman spectroscopy to probe local structural and phase evolution under confinement.

A dedicated photothermal/photoacoustic experimental setup will be developed and optimized for PCM-based nanocomposites. Particular attention will be paid to signal interpretation in the presence of latent heat effects and heterogeneous phase transitions. Extracted thermal transport properties will be cross-validated using complementary techniques to ensure physical consistency.

Scientific Environment

The PhD student will be hosted at LEMTA (Laboratoire Énergies & Mécanique Théorique et Appliquée, UMR 7563), a joint research unit of Université de Lorraine and CNRS. The student will join the TEMIN (Thermal Engineering at Micro- and Nano-scales)team, under the supervision of Prof. David Lacroixand Dr. Mykola Isaiev.

LEMTA provides a unique experimental environment for thermal transport studies, with access to photothermal and photoacoustic techniques, Raman thermometry, infrared thermography, thermoreflectance methods, and scanning thermal microscopy. The project is embedded in a strong international collaboration with Taras Shevchenko National University of Kyiv, enabling complementary atomistic simulations of thermal transport in confined PCMs.

Candidate Profile

Applicants must hold a Master’s degree (or equivalent)in physics, materials science, thermal engineering, or a closely related field.

Required skills and background:

• Solid knowledge of heat transfer and thermal transport properties,
• Experimental experience or strong interest in thermal characterization techniques,
• Ability to perform data analysis and modelingusing Python and/or MATLAB,
• Basic knowledge of optics and electronicsrelevant to experimental setups.

Highly desirable (advantageous) experience:

• Photothermal or photoacoustic experimental techniques,
• Phase-change materials (PCMs) and thermal energy storage systems,
• Non-contact thermal measurements (Raman, IR, thermoreflectance).

Contacts:

Prof. David Lacroix david.lacroix@univ-lorraine.fr
Dr. Mykola Isaiev mykola.isaiev@univ-lorraine.fr