Trapped radical behavior of electron beam irradiated polytetrafluoroethylene fine powder at various temperatures

Oshima, Akira; Horiuchi, Hiroto; Nakamura, Atsushi; Kobayashi, Shun; Terui, Ayana; Mino, Ayano; Shimura, Ryoya; Washio, Masakazu

doi:10.1038/s41598-021-90462-6

Cited by 7 publications

(3 citation statements)

References 25 publications

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“…During the reaction, the electron beam further stimulates the dissociation of C‐F bonds in F‐Si, thereby promoting the formation of C radicals on the surface of F‐Si. [ 48 ] The radicals naturally engage in the crosslinking reaction with the POSS/PVA‐CN oligomer, producing N‐(C) 3 bonds that enable a covalent connection. [ 49 ] Consequently, the ongoing crosslinking reaction eventually establishes an integrated system of F‐Si with E‐GEL via electron beam‐induced covalent linkages, which can serve to effectively alleviate enormous volume changes of F‐Si during battery cycling.…”

Section: Resultsmentioning

confidence: 99%

Formulating Electron Beam‐Induced Covalent Linkages for Stable and High‐Energy‐Density Silicon Microparticle Anode

Je,

Son,

Han

et al. 2024

Advanced Science

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High‐capacity silicon (Si) materials hold a position at the forefront of advanced lithium‐ion batteries. The inherent potential offers considerable advantages for substantially increasing the energy density in batteries, capable of maximizing the benefit by changing the paradigm from nano‐ to micron‐sized Si particles. Nevertheless, intrinsic structural instability remains a significant barrier to its practical application, especially for larger Si particles. Here, a covalently interconnected system is reported employing Si microparticles (5 µm) and a highly elastic gel polymer electrolyte (GPE) through electron beam irradiation. The integrated system mitigates the substantial volumetric expansion of pure Si, enhancing overall stability, while accelerating charge carrier kinetics due to the high ionic conductivity. Through the cost‐effective but practical approach of electron beam technology, the resulting 500 mAh‐pouch cell showed exceptional stability and high gravimetric/volumetric energy densities of 413 Wh kg−1, 1022 Wh L−1, highlighting the feasibility even in current battery production lines.

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Section: Resultsmentioning

confidence: 99%

Formulating Electron Beam‐Induced Covalent Linkages for Stable and High‐Energy‐Density Silicon Microparticle Anode

Je,

Son,

Han

et al. 2024

Advanced Science

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“…So we assumed that the change of average molecular weight was dominant by the scission process. We normalized the difference of average molecular weight by matching the initial average molecular weight to zero, and then we calculated the absolute difference between the initial average molecular weight and after the irradiation as shown in Figure 10 [ 25 , 26 , 27 ]. We compared these differential values with the simulation results of the scission rate.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of Radiation Resistance of Polystyrene Using Molecular Dynamics Simulation

et al. 2022

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The scission rates of polystyrene and fluorinated polystyrene irradiated in an irradiation facility with Co-60 γ-rays were determined using molecular dynamics simulation and gel permeation chromatography (GPC) molecular weight distributions. The prediction was based on the assumption that γ-ray energy is transferred to the initial velocity of the primary knock-on atom. We employed a molecular dynamics simulation procedure to compute the changes in bond length between the connections for selected values of the absorbed dose and compared the calculated values with measurements made on the irradiated samples. The samples were exposed to four different absorbed doses of 25, 50, 75, and 100 kGy. The scission process and scission ratio were simulated with LAMMPS with ReaxFF potential for each bond, and we compared the simulation results with the experimental data especially measuring average molecular weight to evaluate the effect of fluorination on radiation enhancement.

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“…Like PTFE, the ionomer has (C–F) 2 bonding as its polymer principal chain. As is well known, PTFE shows excellent chemical stability but poor resistance to radiation such as electron beam irradiation [ 44 , 45 ]. Therefore, the ionomer in the PEFC catalyst decomposes gradually as a result of observation and analysis in an electron microscope, and this eventually causes morphological change.…”

Section: Discussionmentioning

confidence: 99%

Three-dimensional nanostructure analysis of non-stained Nafion in fuel-cell electrode by combined ADF-STEM tomography

Ube

2024

Microscopy

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The polymer electrolyte fuel cell (PEFC) is one of the strongest candidates for a next-generation power source for vehicles which do not emit carbon dioxide gas (CO2) as exhaust gas. The key factor in PEFCs is the nano-scaled electrochemical reactions that take place on the catalyst material and an ionomer supported by a carbon support. However, because the nano-scaled morphological features of the key materials in the catalyst compound cannot be observed clearly by transmission electron microscopy, improvement of PEFC performance had been approached by an imaginal schematic diagram based on an electrochemical analysis. In this study, we revealed the nano-scaled morphological features of the PEFC electrode in three dimensions and performed a quantitative analysis of the nanostructure by the newly-developed “Combined ADF-STEM tomography technique.” This method combines information from plural ADF detectors with different electron collection angles and can emphasize the difference of the electron scattering intensity between the ionomer and carbon in the cross-sectional image of the reconstructed three-dimensional data. Therefore, this segmentation method utilizing image contrast does not require a high electron beam current like that used in EDX analysis, and thus is suitable for electron beam damage-sensitive materials. By eliminating the process of manually determining the thresholds for obtaining classified component data from grayscale data, the obtained 3D structures have sufficient accuracy to allow quantitative analysis and specify the nano-scaled structural parameters directly related to power generation characteristics.

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Trapped radical behavior of electron beam irradiated polytetrafluoroethylene fine powder at various temperatures

Cited by 7 publications

References 25 publications

Formulating Electron Beam‐Induced Covalent Linkages for Stable and High‐Energy‐Density Silicon Microparticle Anode

Formulating Electron Beam‐Induced Covalent Linkages for Stable and High‐Energy‐Density Silicon Microparticle Anode

Evaluation of Radiation Resistance of Polystyrene Using Molecular Dynamics Simulation

Three-dimensional nanostructure analysis of non-stained Nafion in fuel-cell electrode by combined ADF-STEM tomography

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