Abstract
The ever-increasing enormous consumption of structural materials and fossil fuels in the past decades have catalyzed the urgent need for the high-efficiency energy conservation and storage as well as the stronger (and lighter) structural materials as frames. Introducing multi-scale and pores in bulk materials with characteristic features from nano to micro to macro is able to substantially promote materials’ enhancement and utilization in successfully addressing the above-mentioned issues. The so-called “architected material”, exhibit an extensive application on structural and multi-functional demands as their effective properties are highly defined by the spatial configuration, i.e. the hierarchical architecture and the properties of the solid constituent. Therefore, it holds great promising to facilitate architected materials in solving structural materials and energy challenges in modern industries, by developing advanced micro/nano-manufacturing technologies including top-down and bottom-up routines.Here, we firstly employed a top-down three-dimensional (3D) printing methodology to fabricate composite nano/micro/macro-lattices architectures with superior mechanical performance regarding high specific strength, Young’s modulus, as well as enhanced compressive ability to remain its original integrity in multi-scale and hierarchical architecture. In this process, traditional additive manufacturing (AM) and stereolithography (SLA) as well as state of the art two-photon lithography (TPL) engineering were explored. Benefited from the rationally designed geometry, namely topological structure, and the novel constituent materials, such as high entropy alloy (HEA) or Ni-P metallic glass used in our operating procedure, specialized properties of the lattice structures were thus achieved in catering various structural and functional applications with less consumable structural materials.
As a good candidate for current collector in battery or supercapacitor electrode, the composite micro lattice structures fabricated above were then directly served as the mechanical scaffold for supporting the cellular active materials to realize high capacitive performance in achieving superior energy storage. Also based on the hierarchical and 3D cellular structure-designed concept, 3D hierarchical cellular graphene aerogel was uniformly electrodeposited on the 3D micro scaffold for the first time to sufficiently utilize the active materials with multiscale range. The resultant composite materials not only showed high mechanical property but also exhibit promising energy storage capacity.
To further improve the energy storage ability of the composite materials combined advantages of 3D lattice architectures with hierarchical cellular active materials, the electrochemical performance of the active materials should deserve to have a deep understanding and research to give less materials consume (energy conservation) in energy storage. In this consideration, we focused on the fabrication of multiscale hierarchical 3D cellular active materials, i.e., layered double hydroxides (LDHs), with superior specific capacity、rate capability and long-term cycling ability using bottom-up design strategy. The synthesized specimen not only presented desirable electrochemical performance, but also demonstrated fascinating mechanical stability on micro scale.
In summary, we have successfully used top-down (3D printing) method to fabricate the 3D lattice architectures by rationally integrating with typical topology design for the structural materials conservation in various application, especially, the energy storage application in this thesis. Meanwhile, bottom-up approach was employed to optimizing electrochemical behaviors of the cellular active materials on the mechanically stable lattice collector to achieve high energy output. We anticipated such kind of strategies should shed light on manufacturing various 3D cellular structures with superior mechanical and electrochemical behavior in energy conservation and storage applications.
| Date of Award | 25 Jul 2018 |
|---|---|
| Original language | English |
| Awarding Institution |
|
| Supervisor | Yang LU (Supervisor) & Dong SUN (Co-supervisor) |