Nupur Nikkan Sinha

Synthesis and characterization of single-crystalline α-MoO3 nanofibers for enhanced Li-ion intercalation applications

High quality, single-crystalline alpha-MoO3 nanofibers are synthesized by rapid hydrothermal method using a polymeric nitrosyl-complex of molybdenum(II) as molybdenum source without employing catalysts, surfactants, or templates. The possible reaction pathway is decomposition and oxidation of the complex to the polymolybdate and then surface condensation on the energetically favorable 001] direction in the initially formed nuclei of solid alpha-MoO3 under hydrothermal conditions. Highly crystalline alpha-MoO3 nanofibers have grown along 001] with lengths up to several micrometres and widths ranging between 280 and 320 nm. The alpha-MoO3 nanofibers exhibit desirable electrochemical properties such as high capacity reversibility as a cathode material of a Li-ion battery.

High Rate Capability of Porous LiNi1 / 3Co1 / 3Mn1 / 3O2 Synthesized by Polymer Template Route

Layered LiNi1/3Co1/3Mn1/3O2, which is isostructural with LiCoO2, is considered as a potential cathode material for Li-ion batteries. Submicrometer sized porous particles are useful for high discharge rates. The present work involves a synthesis of submicrometer sized porous particles of LiNi1/3Co1/3Mn1/3O2 using a triblock copolymer as a soft template. The precursor obtained from the reaction is heated at different temperatures between 600 and 900 degrees C for 6 h to get the final product samples. The compound attains increased crystallinity with an increase in the temperature of preparation. However, there is a decrease in the surface area and also in the porosity of the sample. Nevertheless, the LiNi1/3Co1/3Mn1/3O2 sample prepared at 900 degrees C exhibits a high rate capability and stable capacity retention on cycling. The electrochemical performance of LiNi1/3Co1/3Mn1/3O2 prepared in the absence of the polymer template is inferior to that of the sample prepared in the presence of the polymer template

Single-Shot Preparation of Crystalline Nanoplate LiFePO4 by a Simple Polyol Route

Nanoplate LiFePO 4 is synthesized by a polyol route starting from only two reactants, namely, FePO 4 and LiOH. The crystalline compound forms by refluxing a tetraethylene glycol solution consisting of FePO 4 and LiOH at 335°C without further heating of the reaction product. The nanoplates have average dimensions of 30 nm width and 160 nm length, as measured from transmission electron microscopy micrographs. The surface area of the LiFePO 4 sample is 38 m 2 g -1 . Also, the sample is porous with a broadly distributed pore around 50 nm. The electrodes fabricated out of the nanoplate of LiFePO 4 exhibit a high electrochemical activity. Discharge capacity values measured are 160 and 100 mAh g -1 at 0.15C and 3.45C, respectively. A stable capacity of about 155 mAh g -1 is measured at 0.2C over a 50 charge-discharge cycle.