R. Sathiyamoorthi

Electrochemical Characterization of Nanocrystalline LiMxCo1‐xO2 (M=Mg, Ca) Prepared by a Solid‐State Thermal Method

Mg‐doped LiCoO2 and Ca‐doped LiCoO2 are prepared by a solid state thermal method and are used as cathode active materials for lithium ion batteries. The synthesized electrodes are characterized by X‐ray diffraction and SEM studies. LiCoO2 prepared by solid state reaction method, shows a capacity decay over 4.3 V but LiCoO2 doped with Mg and Ca provide an improvement in charge–discharge cycling performance. This effect may be attributed to the fact that Mg2+ and Ca2+ ions have the same size as the Li+ ion and they preferably locate at the inter‐slab space. Therefore, they give a pathway for the intercalation–deintercalation of Li+ during the charge and the discharge studies and prevent distortion of the structure. The products possess good morphology, nano level particle size. The excellent electrochemical performance of the LiMxCo1‐xO2 cathode active material is attributed to the novel preparation and is significant to further studies.

Synthesis and studies of new plasticized PVP: NaClO3 electrolyte system for battery applications

A new thin film sodium ion conducting plasticized polymer electrolyte based on poly(vinyl pyrrolidone) (PVP) complexed with NaClO3 salt systems was prepared by the solution-cast method. The interaction of NaClO3 salt with PVP was confirmed by Infrared (IR) study. Charge transport of these polymer electrolytes is due to ions, which was confirmed by Wagner’s polarization method. From the conductivity measurements, the highest conductivity value 6.71×10−5 S/cm was observed for the composition PVP:PEG:NaClO3(30:60:10) at room temperature 35 °C. The redox behaviour and good reversibility of the plasiticized electrolytes are confirmed by electrochemical techniques. Electrochemical cell studies of these polymer electrolytes were analyzed from their discharge characteristics. The open-circuit voltage (OCV) and short-circuit current (SCC) were found to in the range of 2.52 V to 2.36 V and 760 μA to 1040 μA, respectively.

A new approach to synthesize LiAsF6 and other lithium based fluorochemicals for rechargeable lithium cells

A new method to synthesize inorganic lithium based fluorinated compounds like LiAsF6 (Lithium hexafluoro arsenate) has been developed by a low temperature solid state procedure. LiAsF6 is used extensively in the lithium cells because of its stability to withstand high voltages during cycling. The procedure developed to synthesize lithium based fluorinated compounds is a single step procedure and fluorination is done in-situ. This is an environmentally friendly method and is less expensive than the other known procedures.

A simplified way of sensing gases based on electrochemical cells

A simple approach for sensing gases is reported by employing an electrochemical cell which is fabricated in the general configuration of sodium as anode and a mixture of MnO2 + graphite powder (1:1) as cathode and a polymer electrolyte. The interaction of the mobile sodium ions with the gases at the cathode surface is observed. Fluorine and chlorine gases have been detected which were prepared from mixtures of manganese dioxide with hydrofluoric and hydrochloric acid, respectively. The sensing of gases is based on the observation of voltage and current changes of the electrochemical cell. The working conditions of sensor and the limitations are discussed as well as the basic performance, such as sensitivity, response speed and reproducibility.