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Chemical state

About: Chemical state is a research topic. Over the lifetime, 2378 publications have been published within this topic receiving 78183 citations.


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Journal ArticleDOI
TL;DR: In this paper, the magnetic interactions of oxygen with thin cobalt films were investigated by spin-resolved photoelectron spectroscopy; in particular modifications of surface magnetism depending on the chemical state were determined.

24 citations

Journal ArticleDOI
TL;DR: In this article, the origins of the enhanced ferromagnetism in SrTi1−xCoxO3:H2 nanofibers were analyzed according to the chemical state of Co and the mediation of oxygen vacancies.
Abstract: By employing electrospinning technique, subsequent calcination in air and annealing process in hydrogen, uniform Co-doped SrTiO3 nanofibers with concentrations of Co between 0 and 0.20 were successfully produced. Their morphologies and detailed structures were characterized by scanning electron microscopy, transmission electron microscopy, and X-ray powder diffraction. And, the chemical states of Co were determined by X-ray photoelectron spectroscopy. It was shown that, after calcination, Co2+ was well incorporated into the perovskite structure of SrTiO3, and the nanofibers possessed smooth surface with diameters of 50–100 nm. Magnetic properties of the hydrogen-annealed and -unannealed nanofibers were both measured by physical property measurement system from 50 to 300 K. It was explored that the Co addition and the hydrogen annealing process were both very important to the generation of the observed ferromagnetism in SrTi1−xCoxO3:H2 nanofibers. In hydrogen-annealed SrTi0.80Co0.20O3:H2 nanofibers, a saturation magnetization of 0.74 emu/g and an average moment of 0.122 μB/Co were obtained. The origins of the enhanced ferromagnetism in SrTi1−xCoxO3:H2 nanofibers were analyzed according to the chemical state of Co and the mediation of oxygen vacancies.

24 citations

Journal ArticleDOI
TL;DR: In this article, the authors analyzed possible chemical reactions and their dependence on initial particle associations, i.e. homogeneity of mixing, the physical and chemical state of additives, pressurised sintering environment over the reactants and temperature of sinter.

24 citations

Journal ArticleDOI
TL;DR: In this article, the properties of SiN x layers obtained by plasmaenhanced and low-pressure chemical desorption methods were characterized by AES and XPS and the peak shape and position of the Si LVV line largely depend on the measurement parameters.
Abstract: The properties of SiN x layers are largely influenced by they composition and the chemical state of the constituents. In the present study SiN x layers obtained by plasma-enhanced and low-pressure chemical desorption methods were characterized by AES and XPS. In the case of the most frequently applied AES characterization, the peak shape and position of the Si LVV line largely depend on the measurement parameters

24 citations

Journal ArticleDOI
26 Jan 2021-ACS Nano
TL;DR: In this paper, a chemical approach with a spatial resolution of around 5.6 nm was proposed to imaging degradation heterogeneities and interplay among components in degraded Li-rich cathodes.
Abstract: The capability in spatially resolving the interactions between components in lithium (Li)-ion battery cathodes, especially correlating chemistry and electronic structure, is challenging but critical for a better understanding of complex degradation mechanisms for rational developments. X-ray spectro-ptychography and conventional synchrotron-based scanning transmission X-ray microscopy image stacks are the most powerful probes for studying the distribution and chemical state of cations in degraded Li-rich cathodes. Herein, we propose a chemical approach with a spatial resolution of around 5.6 nm to imaging degradation heterogeneities and interplay among components in degraded Li-rich cathodes. Through the chemical imaging reconstruction of the degraded Li-rich cathodes, fluorine (F) ions incorporated into the lattice during charging/discharging processes are proved and strongly correlate with the manganese (Mn) dissolution and oxygen loss within the secondary particles and impact the electronic structure. Otherwise, the electrode-electrolyte interphase component, scattered LiF particles (100-500 nm) along with the MnF2 layer, is also visualized between the primary particles inside the secondary particles of the degraded cathodes. The results provide direct visual evidence for the Li-rich cathode degradation mechanisms and demonstrate that the low-energy ptychography technique offers a superior approach for high-resolution battery material characterization.

24 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202326
202249
202184
202089
201987
201894