3D Printed, Bioinspired, Soft-Matter Electronics based on Liquid Metal Composites: Eco-Friendly, Resilient, Recyclable, and Repairable

Project Information

Liquid3D

Grant agreement ID: 101045072

DOI

10.3030/101045072

EC signature date 1 August 2022

Start date 1 January 2023

End date 31 December 2027

Funded under

• European Research Council (ERC)

Total cost

€ 2 781 215,00

EU contribution

€ 2 781 215,00

Coordinated by

UNIVERSIDADE DE COIMBRA
Portugal

Periodic Reporting for period 1 - Liquid3D (3D Printed, Bioinspired, Soft-Matter Electronics based on Liquid Metal Composites: Eco-Friendly, Resilient, Recyclable, and Repairable)

Reporting period: 2023-01-01 to 2025-06-30

Summary of the context and overall objectives of the project

Liquid3D proposes bioinspired electronics and machines that are soft, resilient, self-healing, shape-morphing, and fully recyclable. Functional sensing/acting/processing/energy cells will be 3D printed using a series of game changer Liquid Metal based composites. As a result, we will print futuristic soft electronics that sense and interact with humans or the environment. This provides an excellent design freedom to scientists for manufacturing complex “living” electronics, while guaranteeing that any possible product coming from these inventions will be Resilient, Repairable, and Recyclable. I expect that over 80% of microchips, and metals in the printed circuits, can be recovered. Liquid3D redefines the electronics, by rethinking the materials, fabrications, and design architectures.

These objectives are feasible, thanks to the recent breakthroughs that we made to the field. This includes discovery of the biphasic (liquid-solid) composite based on Gallium-Indium Liquid Metal (LM), that allowed the first ever method for room temperature digital printing of stretchable circuits; and as well a method for inclusion of microelectronics into ultra-stretchable circuits through self-soldering, self-healing, and self-encapsulating of LM-Polymer composites.

With Liquid3D we will develop fundamental understanding, and mathematical modelling of biphasic systems, and develops novel room temperature printable composites with sensing/acting/energy storage properties, and methods for recycling them. We will investigate novel forms of implementing truly 3D electronics, with distributed functional cells.
Liquid3D intends to fundamentally rethink, the concept of electronics, as we know today. From rigid and brittle to soft, resilient and repairable; From polluting to recyclable; from battery dependent to self-powered; from 2D to truly 3D; It proposes a radically new way of making “greener” electronics.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During the first 24 months of the project, we focused mostly on the first 3 tasks of the project, while we as well started to tackle the fourth task.

Task 1: State of the Art (SOTA) Review and Detailed Planning (M0-6)
Task 2: Understanding, Modelling, and Synthesis of LM-X-BCP and LM-C(BCP) (M0-42)
Task 3: Development of Functional Cells (M12-48)
Task 4: Systems: The Creator and Creations (M12-60)

Most of efforts were focused on task 2 and task 3. These efforts has already led to development of novel biphasic composites for ultra-stretchable, thin-film energy storage solutions, both as batteries and supercapacitors. These composites improved significantly the state of the art both in stretchable batteries and supercapacitors. To reach this, we addressed three main challenges. 1. How to fabricate stable gallium based electrodes 2. How to protect them against aggressive electrolytes. 3. How to integrate them into stretchable energy storage solutions (i.e. to design the architecture of the battery and supercapacitors). We could successfully address all these challenges, which led to 5 publications in top journals of the field.
These efforts placed our labs at the leading edge of research on gallium based energy storage solutions.

In addition, we developed new biphasic inks for printable stretchable electronics that compared to our previous formulations are more environment friendly, as they are water based and easily recyclable. This ink in terms of performance is very similar to our previous composites. However, it eliminated the need for aggressive solvents such as Toluene.

With the major equipment becoming available to use after a long waiting time, now we are further accelerating our material development process, as we are now able to analyse the microstructure of the composites and inks immediately.

Finally, some of our efforts focused on development of a multi-tool, multi-material additive manufacturing unit for rapid digital printing of soft-matter electronics and robotics. While this is only at its infancy, we are already able to print simple multi-material soft actuators, sensors, and batteries.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

1. Stretchable batteries using Ag-Ga structure demonstrated record-breaking areal storage capacity and stretchability. (2 publications)
2. Graphene Coated liquid metal droplets, could improve the energy storage capacitance of gallium based super capacitors by 27 times, compared to the state of the art (2 publications)
3. We demonstrated the use of core-shell Ag-Ga Nano particles for development of composites with enhanced electrical shielding performance
4. We demonstrated multi-material printing of liquid crystal elastomers for electrically-actuated, 3D printed soft-matter actuators.

Overall we had significant advanced in printed sensors, printed actuators and printed batteries and supercapacitors, that all respect the over all objective of this project, being Resilient, Repairable, and Recyclable (3R).

This Multi-disciplinary research funded by ERC, enabled us to maintain our leading role in liquid metal based electronics. This is already entering a phase where we receive contact from industrial sector, and we feel pressure for scaling these solutions. Therefore, the main need now is extra finance to direct some of the result toward commercial products. Main challenges to be addressed prior to that is sector-specific standardization and validation, and as well demonstration of scalability. To reach that, there is a need for study and synthesis of new ink formulation suitable for the scalable fabrication technique.

erc2.png