Donghua University

About: Donghua University is a education organization based out in Shanghai, China. It is known for research contribution in the topics: Fiber & Nanofiber. The organization has 21155 authors who have published 21841 publications receiving 393091 citations. The organization is also known as: Dōnghuá Dàxué & China Textile University.

In situ Visualization of State-of-Charge Heterogeneity within a LiCoO2 Particle that Evolves upon Cycling at Different Rates

Abstract: For designing new battery systems with higher energy density and longer cycle life, it is important to understand the degradation mechanism of the electrode material, especially at the individual particle level. Using in situ transmission X-ray microscopy (TXM) coupled to a pouch cell setup, the inhomogeneous Li distribution as well as the formation, population, and evolution of inactive domains in a single LiCoO2 particle were visualized as it was cycled for many times. It is found that the percentage of the particle that fully recovered to the pristine state is strongly related to the cycling rate. Interestingly, we also observed the evolution of the inactive region within the particle during long-term cycling. The relationship between morphological degradation and chemical inhomogeneity, including the formation of unanticipated Co metal phase, is also observed. Our work highlights the capability of in situ TXM for studying the degradation mechanism of materials in LIBs.

Nacre-inspired integrated nanocomposites with fire retardant properties by graphene oxide and montmorillonite

Abstract: Natural nacre exhibits extraordinary strong and tough properties with its brick-and-mortar structure that was perfected after millions of years of evolution. Inspired by nacre's hierarchical structure, we fabricated multifunctional bioinspired nanocomposites of graphene oxide (GO) and montmorillonite (MMT) nanosheets with poly(vinyl alcohol) (PVA) via a vacuum-assisted filtration self-assembly process. By combining graphene oxide and montmorillonite with PVA, we demonstrated an effective synergistic toughening effect and obtained integrated strong and tough bioinspired nanocomposites. Furthermore, these nanocomposites show high fatigue-resistant properties, high electrical conductivity and good fire retardant properties. As such, they have promising potential in many applications, including flexible electrodes, flame retardant insulation and as aerospace materials. The technique developed here provides new insights for designing nanocomposites with a complex hierarchical structure that mimic nacre.

Nonlinear oscillator with discontinuity by parameter-expansion method

Abstract: The parameter-expansion method is applied to a nonlinear oscillator with discontinuity. One iteration is sufficient to obtain a highly accurate solution, which is valid for the whole solution domain. Comparison of the obtained solution with the exact one shows that the method is very effective and convenient.