Periodic Reporting for period 1 - UNIYARNS (Universal processing route for high-performance nanostructured yarns)
Berichtszeitraum: 2022-09-01 bis 2025-02-28
Nano-sized materials have outstanding properties particularly relevant for energy storage, energy transfer and mechanical reinforcement. A prevalent challenge is to exploit these properties on the scale of macroscopic engineering components, such as electrodes, cables or structural fibres. Uniyarns bridges the nano and macroscales through a new method of assembly of inorganic nanowires into continuous yarns. Nanowires are grown floating in a gas stream and aggregate into aerogels, porous networks that can be directly spun as yarns and other nanotextile materials. The project pursues an understanding of the chemistry of this process to achieve morphological control at the nanoscale and reaction selectivity to produce high purity yarns on kilometre scale. This will be demonstrated for multiple nanowire chemistries, including compound semiconductors, metal oxides and carbides. The team is also developing a framework to relate bulk yarn properties to their microstructure, for example in terms of the orientation and size distribution of the constituent nanowire population.
The work in this first half revolved predominantly. around building new capabilities for the continuous synthesis of nanowires and developing methods to study reaction selectivity and aerosol dynamics in the gas phase. A dedicated facility for nanowire synthesis and study has been largely completed. It comprises 4 reactors for floating catalyst chemical deposition of different chemistries, instrumentation for in-situ study of evolution of precursors under pyrolysis/CVD, of the catalyst aerosol and of the nanowire networks formed in the gas phase.
One of the main achievements was the demonstration of reaction universality by applying FCCVD to the synthesis of nanowires of SiC, and more recently MOx. In the process of achieving this the group has contributed to the use of simulation and experimental tools for nanomaterials synthesis, respectively in the form of calculate thermodynamic phase diagrams as nanowire growth predictors and gas-phase detection of reaction products to rationalise selectivity. More recently in the project we produced a study of the dynamics of nanowires in the gas phase and introduced a model to describe agglomeration and formation of aerogels as a prelude of freestanding network materials.
One of the main achievements was the demonstration of reaction universality by applying FCCVD to the synthesis of nanowires of SiC, and more recently MOx. In the process of achieving this the group has contributed to the use of simulation and experimental tools for nanomaterials synthesis, respectively in the form of calculate thermodynamic phase diagrams as nanowire growth predictors and gas-phase detection of reaction products to rationalise selectivity. More recently in the project we produced a study of the dynamics of nanowires in the gas phase and introduced a model to describe agglomeration and formation of aerogels as a prelude of freestanding network materials.
The most significant results beyond the state of the art are the demonstration of continuous, scalable synthesis of networks of nanowires. This will have application as electrodes, sensors and other formats. As a first step in this direction the group is conducting electrochemical studies on electrodes for batteries. As nanowires of Si, these electrode represent a step change in performance and the key for the next generation of Li-ion batteries. Furthermore, metal oxide nanowires are being studied by the group for batteries beyond Li-ion.
Another result beyond the state of the art is the introduction of a framework to describe the transition of aerosols of individualised nanowires into aggregated network materials. This is a key step in our efforts to produce continuous yarns of nanowires directly spun from the gas phare during growth by FCCVD.
Finally, we have introduced a method to produce stable dispersions of Si nanowires. This is not only the key to enable wet-processing for a myriad of applications, for example in sensors and optoelectronics, but is also essential to produce macroscopic ensembles with controlled structure and higher degree of alignment.
Another result beyond the state of the art is the introduction of a framework to describe the transition of aerosols of individualised nanowires into aggregated network materials. This is a key step in our efforts to produce continuous yarns of nanowires directly spun from the gas phare during growth by FCCVD.
Finally, we have introduced a method to produce stable dispersions of Si nanowires. This is not only the key to enable wet-processing for a myriad of applications, for example in sensors and optoelectronics, but is also essential to produce macroscopic ensembles with controlled structure and higher degree of alignment.