논문현황

INSTITUTE FOR ADVANCED ENGINEERING

융합소재연구센터 Synthesis of Flower‐like Cu3[MoO4]2O from Cu3(MoO4)2(OH)2 and Its Application for Lithium‐Ion Batteries: Structure‐Electrochemical Property Relationships

· 저자

Basudev Swain, 이덕희, 김준식, 이찬기, 김동완, 박경수


Flower‐like Cu3[MoO4]2O microspheres have been synthesized by using a sequential process from lindgrenite (Cu3(MoO4)2(OH)2). Lindgrenite nanoflowers were synthesized through a simpler route by using an aqueous chemical precipitation technique at room temperature without any surfactants or template. Subsequently, 3D flower‐like Cu3[MoO4]2O microspheres have been synthesized by annealing at 300 °C for 2 h from lindgrenite (Cu3(MoO4)2(OH)2). From the XRD pattern, FTIR spectrum, SEM and TEM analysis, flower‐like Cu3[MoO4]2O (ca. 5 μm) microspheres have been obtained, which were assembled from 3–4 nm thick nanosheets with an orthorhombic structure. Application of 3D flower‐like microspheres as an anode material for lithium‐ion batteries (LIBs) has been investigated and the possible electrochemical mechanism is analyzed. Electrochemical characterization of the Cu3[MoO4]2O nanoflowers as an anode material for LIBs has exhibited good cycle stability and a high coulombic efficiency during operation. The electrochemical activity was attributed to the unique structure of the Cu3[MoO4]2O microspheres, which provide more active sites for Li‐ion storage as well as a reduced transfer resistance. This work has explored a simple synthesis strategy for the synthesis of flower‐like Cu3[MoO4]2O microspheres without templates, additives, or surfactants, which exhibit a basis for not only high electrochemical performance in reversible Li storage, but also cycle stability.


융합소재연구센터 Enhanced electrochemical performance of carbon-coated Li2MnSiO4 nanoparticles synthesized by tartaric acid-assisted sol–gel process

· 저자

박경수, 진연호, 강이승, 이광희, 이남희, 김동완, 홍현선


A tartaric acid-assisted sol–gel process was used to synthesize Li2MnSiO4 (SG-LMS) nanopowders with orthorhombic structures (Pmn21 space group). The Li-active SG-LMS nanoparticles were fully surrounded by a conducting amorphous carbon layer/matrix that was formed by carbonization of the tartaric acid during post-annealing of the dry gel. The SG-LMS electrode exhibited higher specific capacity and superior cycle retention as compared to the LMS electrode prepared by a conventional solid-state reaction. Such high electrochemical performance originated from the presence of a high-purity phase, a large surface area, and an efficient electron transport path facilitated by the conductive carbon coating of the SG-LMS electrode.


융합소재연구센터 Recycling of waste automotive laminated glass and valorization of polyvinyl butyral through mechanochemical separation

· 저자

Basudev Swain, 박재량, 신동윤, 박경수, 홍명환, 이찬기


Due to strong binding, optical clarity, adhesion to many surfaces, toughness and flexibility polyvinyl butyral (PVB) resin films are commonly used in the automotive and architectural application as a protective interlayer in the laminated glass. Worldwide million tons of PVB waste generated from end-of-life automotive associated with various environmental issues. Stringent environmental directive, higher land cost eliminates land filling option, needs a study, we have developed a mechanochemical separation process to separate PVB resins from glass and characterized the separated PVB through various techniques, i.e., scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), infrared spectroscopy (IR) and nuclear magnetic resonance spectroscopy (NMR). Commercial nonionic surfactants D201 used for the mechanochemical separation purpose. Through parameter optimization following conditions are considered to be the optimum condition; 30 vol% D201, stirring speed of 400 rpm, 35 °C temperature, operation time 1 h, and dilute D201 volume to waste automotive laminated glass weight ratio of ≈25. The technology developed in our laboratory is sustainable, environmentally friendly, techno-economical feasible process, capable of mass production (recycling).


융합소재연구센터 Recycling process for recovery of gallium from GaN an e-waste of LED industry through ball milling, annealing and leaching

· 저자

Basudev Swain, Chinmayee Mishra, 강이승, 박경수, 이찬기, 홍현선


Waste dust generated during manufacturing of LED contains significant amounts of gallium and indium, needs suitable treatment and can be an important resource for recovery. The LED industry waste dust contains primarily gallium as GaN. Leaching followed by purification technology is the green and clean technology. To develop treatment and recycling technology of these GaN bearing e-waste, leaching is the primary stage. In our current investigation possible process for treatment and quantitative leaching of gallium and indium from the GaN bearing e-waste or waste of LED industry dust has been developed. To recycle the waste and quantitative leaching of gallium, two different process flow sheets have been proposed. In one, process first the GaN of the waste the LED industry dust was leached at the optimum condition. Subsequently, the leach residue was mixed with Na2CO3, ball milled followed by annealing, again leached to recover gallium. In the second process, the waste LED industry dust was mixed with Na2CO3, after ball milling and annealing, followed acidic leaching. Without pretreatment, the gallium leaching was only 4.91 w/w % using 4 M HCl, 100 °C and pulp density of 20 g/L. After mechano-chemical processing, both these processes achieved 73.68 w/w % of gallium leaching at their optimum condition. The developed process can treat and recycle any e-waste containing GaN through ball milling, annealing and leaching.


융합소재연구센터 Recycling of metal-organic chemical vapor deposition waste of GaN based power device and LED industry by acidic leaching: Process optimization and kinetics study

· 저자

Basudev Swain, Chinmayee Mishra, 강이승, 박경수, 이찬기, 홍현선, 박정진


Recovery of metal values from GaN, a metal-organic chemical vapor deposition (MOCVD) waste of GaN based power device and LED industry is investigated by acidic leaching. Leaching kinetics of gallium rich MOCVD waste is studied and the process is optimized. The gallium rich waste MOCVD dust is characterized by XRD and ICP-AES analysis followed by aqua regia digestion. Different mineral acids are used to find out the best lixiviant for selective leaching of the gallium and indium. Concentrated HCl is relatively better lixiviant having reasonably faster kinetic and better leaching efficiency. Various leaching process parameters like effect of acidity, pulp density, temperature and concentration of catalyst on the leaching efficiency of gallium and indium are investigated. Reasonably, 4 M HCl, a pulp density of 50 g/L, 100 °C and stirring rate of 400 rpm are the effective optimum condition for quantitative leaching of gallium and indium.


융합소재연구센터 Synthesis of Cu3(MoO4)2(OH)2 nanostructures by simple aqueous precipitation: understanding the fundamental chemistry and growth mechanism

· 저자

Basudev Swain, 이덕희, 박재량, 이찬기, 이근재, 김동완, 박경수


Lindgrenite (Cu3(MoO4)2(OH)2) nanoflowers were synthesized through the simplest possible route by an aqueous chemical precipitation technique at room temperature without using any surfactants, template, expensive chemicals, complex instrumentation or tedious multistage synthesis process. Their morphology, structure, thermal properties, surface area, synthesis chemistry, and structural and growth mechanisms involved in the synthesis process were analyzed. Using XRD, FE-SEM, HR-TEM and FT-IR spectroscopy, their structure and morphology were analyzed. The thermal stability, surface area and porosity of the Cu3(MoO4)2(OH)2 nanoflowers were analyzed by TGA and BET. XRD analysis showed that the Cu3(MoO4)2(OH)2 nanoflowers have a pure monoclinic structure. The morphological analysis showed that the Cu3(MoO4)2(OH)2 nanoflowers are ∼10 μm in size, which are formed from self-assembly of thin nanosheets with a thickness of ∼20 nm. TGA indicated that the Cu3(MoO4)2(OH)2 nanoflowers are stable materials up to 328 °C and the isotherm from BET analysis indicated that the Cu3(MoO4)2(OH)2 nanoflowers are non-porous materials. The BET surface area of the synthesized Cu3(MoO4)2(OH)2 nanoflowers was found to be 21.357 m2 g−1. Moreover, the effects of the pH value and reaction time on the morphology of the Cu3(MoO4)2(OH)2 nanoflowers were studied and their optimization was performed. The results of the optimization study indicated that the reaction time and pH are two important parameters influencing the nucleation, growth, morphology, and synthesis mechanism. These flower-shaped Cu3(MoO4)2(OH)2 nanostructures are promising precursors for preparing molybdenum oxide materials which have various applications and can be synthesized in a very simple one-pot reaction system using commonly available chemicals without using a complex route.


융합소재연구센터 Synthesis of cosmetic grade TiO2-SiO2 core-shell powder from mechanically milled TiO2 nanopowder for commercial mass production

· 저자

Basudev Swain, 박재량, 박경수, 이찬기


TiO2 nanoparticles as an active sunscreen ingredient generate reactive oxygen species (ROS) upon UVA irradiation which is cytotoxic, genotoxic and potential to damage the DNA. The health concern and potential risks from TiO2 can be mitigated by shielding the particles through the suitable coating. Considering the advantages of SiO2, SiO2 coated TiO2 nanoparticles can be a potential material which can replace TiO2 for thickening, whitening, lubricating, and sunscreen ingredient in cosmetics. This article reports the synthesis of cosmetic grade TiO2-SiO2 core-shell nanopowder from mechanically milled TiO2 nanopowder for commercial mass production. From commercial TiO2 nanopowder was fabricated through size reduction by nanoset milling. Followed by the fabricated TiO2 nanopowder coated with SiO2 through sol-gel technique. A suitable optimum condition was explored for cosmetic grade TiO2-SiO2 core-shell nanopowder. Various physical properties and optical properties were analyzed. Synthesized of cosmetic grade TiO2-SiO2 core-shell nanopowder found to be at 100 nm size, with a homogeneous SiO2 coating having UVA protection factor 39 and sun protection factor (SPF) is 42. From the size, safety, and SPF perspective it can be an excellent cosmetic grade powder and from process simplicity perspective it can be commercially viable.


융합소재연구센터 One-pot wet chemical synthesis of fluorine-containing TiO2 nanoparticles with enhanced photocatalytic activity

· 저자

이덕희, Basudev Swain, 신동윤, 안낙균, 박재량, 박경수


Two types of TiO2 nanoparticles: i) fluorine-containing TiO2 (F-TiO2) and ii) fluorine-free TiO2 (H-TiO2) nanoparticles, were prepared through a simple, scalable wet-chemical synthesis process, and a comparative study of their photocatalytic properties was conducted. This facile process begins with a one-pot precipitation process at 90 °C, followed by heat treatment at 600 °C for 1 h in air, resulting in hierarchical, sphere-like, mesoporous structures composed of primary nanoparticles. The microstructural features and crystallographic structures of both types of nanoparticles were systematically investigated by X-ray diffraction, thermogravimetric/differential thermal analysis, X-ray photoelectron spectroscopy, N2 physical adsorption-desorption, field emission scanning electron microscopy, and transmission electron microscopy analyses. The photocatalytic activities were also evaluated by measuring the degradation of MB. The F-TiO2 nanoparticles showed enhanced photocatalytic activity compared to H-TiO2, which can be attributed to adsorbed fluorine on the surface which leads to various positive effects on the photocatalytic degradation reactions.