Subramanian Venkatachalam

High capacity anode materials for lithium ion batteries

Na-ion batteries are an attractive alternative to Li-ion batteries for large-scale energy storage systems because of their low cost and the abundant Na resources. This Review provides a comprehensive overview of selected anode materials with high reversible capacities that can increase the energy density of Na-ion batteries. Moreover, we discuss the reaction and failure mechanisms of those anode materials with a view to suggesting promising strategies for improving their electrochemical performance.

In-Situ Formation of Sandwiched Structures of Nanotube/CuxOy/Cu Composites for Lithium Battery Applications

Development of materials and structures leading to lithium ion batteries with high energy and power density is a major requirement for catering to the power needs of present day electronic industry. Here, we report an in situ formation of a sandwiched structure involving single-walled carbon nanotube film, copper oxide, and copper during the direct synthesis of nanotube macrofilms over copper foils and their electrochemical performance in lithium ion batteries. The sandwiched structure showed a remarkably high reversible capacity of 220 mAh/g at a high cycling current of 18.6 A/g (50 C), leading to a significantly improved electrochemical performance which is extremely high compared to pure carbon nanotube and any other carbon based materials.

Evidence for the existence of multiple equilibrium states in cobalt phthalocyanine tetramer: a study by dielectric spectroscopy

In any investigation, information about the molecules under consideration is very essential for tailoring their properties. Evaluation of dispersion parameters, namely optical dielectric constant, static dielectric constant, relaxation time and spreading factor, assumes significance in this context. Dielectric spectroscopy is a useful tool for estimating these parameters. Not only does it reveal details about these constants but it also gives insight into the mechanism of conduction. In this paper the evaluation of dispersion parameters of cobalt phthalocyanine tetramer in the temperature range 300–393 K is attempted using Cole–Cole plots. The temperature variation of the spreading factor indicates the existence of multiple equilibrium positions in the case of cobalt phthalocyanine tetramer. To the best of our knowledge, the evaluation of dispersion parameters for cobalt phthalocyanine tetramer is reported for the first time.