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The Role of Nanosized Materials in Lithium Ion Batteries
Published in Nandakumar Kalarikkal, Sabu Thomas, Obey Koshy, Nanomaterials, 2018
Bibin John, C. P. Sandhya, C. Gouri
Orthosilicate is a class of polyanionic cathode material having high capacity for application in next generation Li-ion batteries.40 The main disadvantage of silicate family is their low electronic conductivity, which is about three orders of magnitude lower than that of LiFePO4.41 Murliganth et al. synthesized carbon coated Li2FeSiO4 nanoparticles of 20 nm size. The Li2FeSiO4/C sample showed excellent rate performance and cyclic stability with stable discharge capacities of 148 mAhg−1 at 25°C and 204 mAhg−1 at 55°C. Li2MnSiO4/C showed severe capacity fading especially at elevated temperatures. This poor capacity retention of Li2MnSiO4 is due to the presence of Mn3+ ions, which causes J-T distortion and manganese dissolution as in case of spinel LiMn2O4.42
κ dielectrics
Published in Michel Houssa, κ Gate Dielectrics, 2003
Gian-Marco Rignanese, Xavier Gonze, Alfredo Pasquarello
Due to the chemical homology of Hf and Zr discussed in the ‘Introduction’ section, hafnon (HfSiO4) and zircon (ZrSiO4) resemble each other in many physical and chemical properties. Their similarities are such that there is complete miscibility between ZrSiO4 and HfSiO4 [54]. In addition to their importance as potential alternative gate dielectrics, hafnon and zircon are of geological significance. They both belong to the orthosilicate class of minerals, which can be found in igneous rocks and sediments. Zircon is used as a gemstone, because of its good optical quality, and resistance to chemical attack. In the earth’s crust, hafnon and zircon are host minerals for the radioactive elements uranium and thorium. Therefore, they have been widely studied in the framework of nuclear waste storage.
Reactions on Polymers
Published in Charles E. Carraher, Carraher's Polymer Chemistry, 2017
Synthetic shapes are generally limited to sheets and polyhedral structures. Yet, nature produces a much wider variety of shapes, including curves, spirals, ripples, bowls, pores, tunnels, spheres, and circles. We are beginning to master such shapes. We are also beginning to make these shapes based on especially “grown” shapes that act as templates for further growth. For instance, Geofreey Ozin and coworkers mixed together alumina, phosphoric acid, and decylamine in an aqueous solution of tetraethylene glycol. After a few days, millimeter-sized aluminophosphate solid spheres and hollow shells were formed with the surfaces sculpted into patterns of pores, meshes, ripples, bowls, etc. A decylammonium dihydrogenphosphate liquid-crystal phase was formed and this surfactant, along with the glycol, was forming bilayer vesicles. The vesicles acted in different ways with some fusing to one another and others splitting apart or collapsing, giving a variety of structures. Thus, appropriate conditions can be selected that favor certain template structures, producing an array of geometric structures. Further, the templates themselves can be used to make selective separations. In a related study, the group employed a silica precursor, tetraethyl orthosilicate. Here, the orthosilicate units assembled together, forming micelles that in turn acted as liquid-seed crystals, growing other assemblies with varying shapes. Rapid growth in the axial direction produces rope-like structures that can be made to form circles and loops through the application of external forces. Other structures included egg shapes, disks, spirals, knots, and spheres.
Adsorption and desorption characteristics of metal(oid)s in the yellow soils of a typical karst area, southwest China
Published in Soil and Sediment Contamination: An International Journal, 2022
Jiachun Zhang, Zhenming Zhang, Xianfei Huang, Mingyang Cui, Xianliang Wu, Huijuan Liu
Figure 2 and Table 3 demonstrates that the adsorption and desorption relationships of metal(oid)s in yellow soil under the different clay levels. The maximum adsorption of Pb, Cd, Zn, Cu, Cr, Hg and As were observed at 410 mg/kg, 230 mg/kg, 105, no detect, 299, 148, 110 mg/kg, respectively. The maximum desorption of Pb, Cd, Zn, Cu, Cr, Hg and As was reached at 188, 303, 478, 357,341, 434, 483, mg/kg. The adsorption by yellow soil of metal(oid)s improved with an increasing clay content. The reason may be that the chemical composition of clay particles mainly included silicate minerals. Silicate minerals will hydrolyze in an aqueous environment, producing silicic acid (H2SiO3) and orthosilicate (H4SiO4), while orthosilicate will generate SiO2 gel (Brutchey and Morse 2009). This is a porous solid gel that has good adsorbability; therefore, it obviously promotes the adsorption of metal(oid)s. The desorption of metal(oid)s in the yellow soil did not vary with increasing clay levels. Presumably, the increase in clay content was attributable to the increase in the unit mass contact area (the porous silica gel increased the adsorption capacity of metal(oid)s onto the soil).
Electromagnetic interference shielding effectiveness of sol-gel coating on Cu-plated fabrics
Published in The Journal of The Textile Institute, 2021
P. V. Kandasaamy, M. Rameshkumar
In this work, Triethoxyvinylsilane (TVS), Triethoxyphenylsilane (TPS), Vinyltrimethoxy-silane (VTMS), Tetramethyl orthosilicate (TMOS) and Tetraethyl orthosilicate (TEOS) were used as precursors. For coating, the sol-gel was synthesized by mixing of precursor, deionized water and solvent (Ethanol) with the molar ratio of 1:4:8 respectively (Periyasamy et al., 2019). Later the mixture was adjusted with the pH of 3 by using of 0.1 M of Nitric acid. The mixture was kept for 8 h at room temperature with air-tight container under stirrer conditions (300 rpm) to ensure the components had sufficient time to react with each other properly. After 8 h, the sol-gel was ready to be applied on the Cu coated fabric. Padding mangle was used for sol-gel coating on the metal coated fabrics. The fabric was padded with 80% expression. Then, the fabric was dried in atmospheric temperature and cured at 130 °C for 5 min.
Polymer-hybrid silica composite for the azo dye removal from aqueous solution
Published in Journal of Dispersion Science and Technology, 2019
Andrzej Sienkiewicz, Agnieszka Kierys, Jacek Goworek
The Amberlite resin XAD7 HP (XAD7) and both silica precursors (tetramethyl orthosilicate – TMOS and [3-(2-aminoethylamino)propyl]trimethoxysilane – AAPTS were supplied by Sigma Aldrich. The sodium hydroxide (POCH), anhydrous ethanol (POCH), hydrochloric acid (Chempur, 36%) and ammonia solution (Chempur, 25%) were provided by Polish manufacturers in analytical grade purity. The azo dye – Cochineal Red A (E124) was bought at a local grocery store (food additive purity). The Si40 silica gel used for comparative adsorption of the azo dye was of chromatographic grade and was manufactured by Merck. The solutions were prepared with redistilled water. All reagents were used without any further purification, except for the Amberlite resin, which was thoroughly rinsed with redistilled water in order to remove salt from XAD7, since the manufacturer distributes its product swollen in salt solution. Subsequently, the polymer spheres were dried in regular and vacuum drier at 80 °C for minimum 12 h.