screening-coatings-for-an-all-solid-state-battery-using-situ

Screening of Coatings for an All-Solid-State Battery Using <em>In Situ</em> Transmission Electron Microscopy

With the ever-increasing use of Li-ion batteries, especially due to their adoption in electric vehicles, their safety is in prime focus. Thus, the ...

Forschungszentrum Jülich GmbH

Polyacrylonitrile-based carbon nanofibers (PAN-based CNFs) have great potential to be used for carbon dioxide (CO) capture due to their excellent CO adsorption properties. The porous structure of PAN-based CNFs originates from their turbostratic structure, which is composed of numerous disordered stacks of graphitic layers. During the carbonization process, the internal structure is arranged toward the ordered graphitic structure, which significantly influences the gas adsorption properties of PAN-based CNFs. However, the relation between structural transformation and CO capture is still not clear enough to tune the PAN-based CNFs. In this paper, we show that, with increasing carbonization temperature, the arrangement of the PAN-based CNF's structure along the stack and lateral directions takes place independently: gradually aligning and merging along the stack direction and enlarging along the lateral direction. Further, we correlate the structural arrangement and the CO adsorption properties of the PAN-based CNFs to propose a comprehensive structural mechanism. This mechanism provides the knowledge to understand and tailor the gas adsorption properties of PAN-based CNFs.

Structural Study of Polyacrylonitrile-Based Carbon Nanofibers for Understanding Gas Adsorption.

Conformal coating of silicon (Si) anode particles is a common strategy for improving their mechanical integrity, to mitigate battery capacity fading due to particle volume expansion, which can result in particle crumbling due to lithiation induced strain and excessive solid-electrolyte interface formation. Here, we use  transmission electron microscopy in an open cell to show that TiO coatings on Si/SiO particles undergo thickness dependent rupture on battery cycling where thicker coatings crumble more readily than thinner (∼5 nm) coatings, which corroborates the difference in their capacities.

 transmission electron microscopy of battery cycling: thickness dependent breaking of TiO coating on Si/SiO nanoparticles.

Liquid phase transmission electron microscopy (TEM) provides a useful means to study a wide range of dynamics in solution with near-atomic spatial resolution and sub-microsecond temporal resolution. However, it is still a challenge to control the chemical environment (such as the flow of liquid, flow rate, and the liquid composition) in a liquid cell, and evaluate its effect on the various dynamic phenomena. In this work, we have systematically demonstrated the flow performance of anliquid TEM system, which is based on 'on-chip flow' driven by external pressure pumps. We studied the effects of different chemical environments in the liquid cell as well as the electrochemical potential on the deposition and dissolution behavior of Cu crystals. The results show that uniform Cu deposition can be obtained at a higher liquid flow rate (1.38l min), while at a lower liquid flow rate (0.1l min), the growth of Cu dendrites was observed. Dendrite formation could be further promoted byaddition of foreign ions, such as phosphates. The generality of this technique was confirmed by studying Zn electrodeposition. Our direct observations not only provide new insights into understanding the nucleation and growth but also give guidelines for the design and synthesis of desired nanostructures for specific applications. Finally, the capability of controlling the chemical environment adds another dimension to the existing liquid phase TEM technique, extending the possibilities to study a wide range of dynamic phenomena in liquid media.

Article	Year
Structural Study of Polyacrylonitrile-Based Carbon Nanofibers for Understanding Gas Adsorption. ACS applied materials & interfaces\| PubMed ID: 34546700	2021
transmission electron microscopy of battery cycling: thickness dependent breaking of TiO coating on Si/SiO nanoparticles. Chemical communications (Cambridge, England)\| PubMed ID: 35129189	2022
Nanoscale visualization of metallic electrodeposition in a well-controlled chemical environment. Nanotechnology\| PubMed ID: 35878519	2022

Shibarata Basak

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