Side-View Operando Optical Microscopy Analysis of a Graphite Anode to Study Its Kinetic Hysteresis

Operando analyses have provided several breakthroughs in the construction of high-performance materials and devices, including energy storage systems. However, despite the advances in electrode engineering, the formidable issues of lithium intercalation and deintercalation kinetics cannot be investigated by using planar observations. This study concerns side-view operando observation by optical microscopy of a graphite anode based on its color changes during electrochemical lithiation. Since the graphite color varies according to the optical energy gap during lithiation and delithiation, this technique can be used to study the corresponding charge-discharge kinetics. In addition, the cell configuration uses liquid electrolytes similar to commercial cells, allowing practical application. Furthermore, this side-view observation has shown that microscale spatial variations in rate and composition control the insertion and deinsertion, revealing the kinetics throughout the whole electrode. The results of this study could enhance the fundamental understanding of the kinetics of battery materials

Synthesis and Electrical Properties of Polyaniline/Polyaniline Grafted Multiwalled Carbon Nanotube Mixture via Suspension Polymerization

Interdisciplinary School of Green EnergyThe mixture of polyaniline (PANi) and PANi-grafted multiwalled carbon nanotube (PANi/PANi-g-MWNT mixture) was prepared by suspension polymerization. MWNT was first functionalizaed with 4-aminobenzoic acid via “direct” Firedel-Crafts acylation in polyphosphoric acid (PPA)/phosphorous pentoxide (P2O5) medium to afford 4-aminobenzoyl-functionalized MWNT (AF-MWNT). The resulting 4-aminobenzoyl-functionalized multiwalled carbon nanotube was then treated with aniline in the presence of ammonium persulfate/aqueous hydrochloric acid to promote a suspension polymerization. The resultant composite was characterized by elemental analysis, Fourier-transform infrared spectroscopy, wide angle x-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-vis absorption spectroscopy, florescence spectroscopy, cyclic voltammetry, and electrical conductivity measurement. The electrical conductivity of polyaniline grafted multiwalled carbon nanotube composite was improved compared to that of polyaniline control. Specifically, the electrical conductivity of polyaniline grafted multiwalled carbon nanotube was improved 1.5~3500 times depending upon the level of doping of what. The capacitance of the composite was also greatly enhanced.ope

Feasibility Analysis of Estrification Systems with Entrainers

(Ethyl Acetate) and IPA (Isopropyl Acetate) production systems are studied in terms of the feasibility analysis. It is not feasible to retrieve pure products by a simple reactive distillation for IPA production system because CCR (Critical Composition Region) covers the entire desired binary edge for IPA system. On the other hand, even though CCR does not cover the entire desired binary edge of the EA system completely, internal reflux ratio (IRR) analysis does not allow the production of the pure product via reactive distillation for EA production system. To overcome the restraints, external entrainers are utilized to take advantage of liquid-liquid split of the lowest boiling azeotrope between the entrainer and water, which is one of the desired products in esterification production systems. Dichloromethane and trichloromethane are the entrainers that are very toxic, yet still conventionally used for production of those esters mentioned above. In this paper, n-hexane and n-pentane are introduced as alternative entrainers because these are more environmentally benign chemicals and less toxic compared to dichloromethane and trichloromethane (chloroform)

Abstract Painting and the Aesthetics of Moderation

The journey of this research began with exploring the notion of invisible space which cannot be perceived by the human eye, and the process of image visualisation expressed through my abstract paintings, which is supported by my theoretical research. ‘Invisible Space’, the title of one of my recent paintings, evokes the notion of a very small space such as a cell or nerve tissues which form part of the human body and have the potential to simultaneously symbolise a cosmological space. In my practice, I adopt painting as a pertinent method to realise my subjects and motifs. I consider how my painting is situated in contemporary art theory and practice by exploring artists and writers relevant to my underlying concept. I explore how my subject is presented in painting and drawing, and how my research can be developed logically and systematically in response to my practice. In this report, I analyse the three key elements: 1) abstraction that explores macro & micro space; 2) colour experiments and 3) cultural traditions and gesture through Korean Monochrome painting