Polymeric reversible conductive adhesive for recyclable electronics
Electronic devices contain valuable and noxious metals that are today hardly recovered. While the demand for electronics is still growing, the urge for recyclable electronics development grows stronger. Printed Circuit Boards (PCB) are the core of electronics and contain electronic component that are fixed onto metal tracks through conductive adhesives. Such adhesives contain generally a metallic filler and a polymeric binder that is generally a polymerizable thermoset formulation.
With the increasing topics on material circularity, self-immolative polymers (SIP), polymer systems that have the ability to undergo depolymerization with a stimulus, have emerged in the recent years as viable systems to bring recyclability to polymer materials.
The current post-doc will develop a polymerizable SIP binder to be used in conductive adhesive in PCB applications. After the selection of adequate chemistries, the post-doc will synthesize SIP and evaluate their thermal and mechanical properties and their ability to depolymerize under stimulus. In a second step, the most promising SIP will be formulated as a conductive adhesive and will be applied to a PCB. The recyclability of the final object will be studied.
Post-Doc - Research Engineer In-situ characterization coupled with electro-reduction of CO2
This project concerns the Circular Carbon Economy program. It proposes mature solutions for industrial decarbonization based on electrochemical CO2 recovery. The candidate will be in charge of developing an electrolyzer for optimized conversion of CO2 into CO; a key molecule in the synthesis of many carbon-based products; by integrating in-situ characterization resources (UV-Vis, Infra-Red). The development of customized cells coupled with this local characterization, should enable to gain a better understanding of reaction phenomena, determine the diffusion mechanisms of species in the electrolytic medium, and extend the analysis to the entire electrochemical system. Studies and experiments will allow to optimize not only the catalytic system, but also the various cell components (membrane, electrode, Gas Diffusion Layer / Gas Diffusion Electrode, electrolyte, CO2 routing), in order to propose innovative, high-performance electrolyzer designs.
Design and fabrication of magnetic cores having permeability gradient using additive manufacturing
As a major technological research institute, the CEA-Liten plays a decisive role in the development of future technologies for the energy transition and the limitation of greenhouse gas emissions. The laboratory develops magnetic components working at high frequency (> 100 kHz) for an integration in compact power electronics converters. Today, the discrete magnetic components are among the most bulky parts in the power converters (~30-40%) and they are responsible of almost 40-50% of the heat losses. The advent of wide band gap semiconductors (SiC or GaN) increases the switching frequency to values above 100 kHz. This strategy helps to reduce, theoretically, the dimensions of the passives but the thermal constraints (due to the losses produced at a higher frequency) and the electromagnetic compatibility (EMC; due to the noise emerging from faster switching commutations) may constitute an issue (in a system approach). In this sense, the developments of new architectures (based on advanced core geometries or clever magnetic materials arrangements) may constitute a breakthrough. The diversity of present cores and fabrication technologies permit small incremental gains on these magnetic components integrations. Additive manufacturing is a very emerging fabrication process that allow not only developing new core geometry but also, the adjustment of core composition (by allowing the deposition of layers containing different ferrite powder composition). The post-doctoral fellow will work on the design of a core having a permeability gradient and on its electrical and thermal characterizations. The post-doctoral fellowship is of 2 years duration located in the city of Grenoble (France) with a minimum wage of 40 k€ per year. If you want to have more detail please use the following link: https://liten.cea.fr/cea-tech/liten/Documents/Postdoc-Carnot-EF/AMbassador.pdf
Thermal conductor and electrical insulator nanocomposite for thermal management of 3D printed battery systems
Developments in energy transport and storage technologies (fast-charge technologies, high energy density batteries) mean that these systems generate considerably more heat during operation. In addition, the ever-increasing drive to miniaturise embedded systems is constantly reducing the space allocated to cooling, leading to the obsolescence of forced convection cooling systems (active systems) and inevitably affecting their performance, lifespan and reliability. These various factors inevitably lead to the need to develop a new class of materials that dissipate heat via their own structure.
The original strategy proposed consists of manufacturing thermally conductive and electrically insulating nanocomposites loaded with 1D and 2D nanoparticles with a rheology that is suitable for the 3D additive manufacturing process (FDM, Fused Deposition Modeling).
To this end, you will develop an insulating coating on the surface of conductive nanofillers using a sol-gel process, and the influence of the various synthesis parameters (T, pH, coupling agent, precursor rate, etc.) on the homogeneity and thickness of the shell will be studied and optimised. In addition, in order to reduce phonon diffraction at the nanofiller/matrix interface, surface functionalisation will be evaluated. Finally, the development of the nanocomposite, the manufacture of printable filaments and the shaping by 3D printing (fused deposition modeling - FDM) will be studied in order to optimize the thermal management of the battery casing. The anisotropy of the nanocomposite resulting from the morphology of the nanoparticles, combined with the printing process and the innovative design of the passive system, will optimise the thermal management of the entire module
Batteries recycling :Development and understanding of a new deactivation concept of lithium ion domestic batteries
Domestic lithium ion batteries gather all batteries used in electronic devices, mobile phone, and tooling applications. By 2030, the domestic lithium-ion battery market will increase up to 30%. With the new European recycling regulation and the emergency to find greener and safer recycling process, it is today necessary to develop new deactivation process of domestic lithium ion batteries.
The process has to address several lithium ion chemistries, be continuous, safe, controllable and low cost.
To develop this new concept, the first step will be to define the most appropriate chemical systems. Then these chemical systems will be tested in a dedicated experimental laboratory setup using chemistry and electrochemistry, allowing the simulation of real conditions of domestic batteries deactivation.
The third step will be to characterize, understand and validate the electrochemical and physico chemical mechanisms. The last step will be to participate to the validation of the deactivation concept on a real object (a lap top battery) in representative conditions (on the abuse tests plateform of CEA).
Innovative biobased vitrimer electrolytes for self-healable and recyclable Li metal batteries
This post-doctoral position is part of the « ELECTRIMER » project, which aims to reduce the environmental impact and to improve the safety of the future Li-metal batteries. In this contexte, the recruited researcher will develop a new self-healable and extrudable Gel Polymer Electrolyte (GPE). Biobased monomers of generations 2 and 3 (not in competition with the food industry) will be used to synthesize a new polymer, that will be swollen with green and safe solvents. A vitrimer chemistry will be integrated in the polymer structure, in order to improve the batterie durability, by introducing self-healing properties to the GPE. The reversible chemistru will also allow to improve the batterie recyclability.
simulation of bi-metallic componants by 3D printing
This position will take place in the frame of MADE 3D European project. The objective of this is to build and run numerical simulations of bi-material L-PBF process taking account both thermal and mechanical behaviors. ANSYS© software will be used for this work. Numerical results will be compared to experimental results from Dedicated samples wich will be designed and manufactured by the post-doctoral student.
High entropy alloys determination (predictive thermodynamics and Machine learning) and their fast elaboration by Spark Plasma Sintering
The proposed work aims to create an integrated system combining a computational thermodynamic algorithm (CALPHAD-type (calculation of phase diagrams)) with a multi-objective algorithm (genetic, Gaussian or other) together with data mining techniques in order to select and optimize compositions of High entropy alloys in a 6-element system: Fe-Ni-Co-Cr-Al-Mo.
Associated with computational methods, fast fabrication and characterization methods of samples (hardness, density, grain size) will support the selection process. Optimization and validation of the alloy’s composition will be oriented towards two industrial use cases: structural alloys (replacement of Ni-based alloys) and corrosion protection against melted salts (nuclear application)
Lean-Rare Earth Magnetic materials
The energy transition will lead to a very strong growth in the demand for rare earths (RE) over the next decade, especially for the elements (Nd, Pr) and (Dy, Tb). These RE, classified as critical materials, are used almost exclusively to produce NdFeB permanent magnets, and constitute 30% of their mass.
Several recent international studies, aiming to identify new alloys with low RE content and comparable performances to the dense magnetic phase Nd2Fe14B, put hard magnetic compounds of RE-Fe12 type as advantageous substitution solutions, allowing to reduce more that 35% of the amount of RE, while keeping the intrinsic magnetic properties close to those of the Nd2Fe14B composition.
The industrial developments of the RE-Fe12 alloys cannot yet be considered due to the important technological and scientific challenge that remain to be lifted in order to be able to produce dense magnets with resistance to demagnetization sufficient for current applications (coercivity Hc > 800 kA/m).
The aim of the post-doctoral work is to develop Nd-Fe12 based alloys with optimized intrinsic magnetic properties and to master the sintering of the powders in order to obtain dense magnets with coercivity beyond 800 kA/m, to fulfil the requirements of the applications in electric mobility. Two technological and scientific challenges are identified:
- understanding of the role of secondary phases on the coercivity. This will open the way to the implementation of techniques called "grain boundary engineering", well known for the NdFeB magnets to have remarkably improved the resistance to demagnetization.
- mastering the sintering step of these powders at low temperature (< 600°C) in order to avoid the decomposotion of the magnetic phase by grain boundary engineering
Wood modifications by supercritical CO2
In order to replace current high environmental impact construction materials, CEA leads research work on chemical functionalization of wood (from French local forests) to improve its properties and make them a viable substitute of these construction materials or imported construction wood.
In this frame, chemistry under supercritical CO2 appears to be an efficient way to carry innovative chemistries while liùmiting the environmental impact & VOCs emissions of such processes.
Thus, you will be in charge of the development of new processes of chemical modification of local wood species under supercritical CO2. You will lead the research project by perfroming the state of the art, making technical propositions (around the adapted functionalization chemistries), carrying out the eperiments & the characterizations and will be in charge of respecting the deadlines & redacting the associated deliverables.