K. Ramya

Development of polymer electrolyte membrane fuel cell stack

Abstract The proton exchange membrane fuel cell (PEMFC) is one of the strongest contenders as a power source for space, electric vehicle and domestic applications. Since 1988 intensive research is being carried out at our centre to develop PEMFCs. The main RandD activities are: (i) to develop a method for the electrode preparation (ii) to enhance platinum utilisation using low platinum loading and (iii) to design multicell stacks. The results of RandD development of the above activities are discussed in this paper.

Electrochemical studies on the effect of nickel substitution in TiMn2 alloys

Abstract Effect of nickel substitution on the electrochemical hydriding and dehydriding behavior of TiMn2 type hydrogen storage alloys in 6 M aqueous KOH solution was investigated. The electrode characteristics of TiMn2−xNix (x=0.0–0.5), such as discharge capacity, high rate dischargeability and cycle life, indicate that addition of nickel in the alloy increases the discharge capacity and cycle life characteristics of the alloy. The electrochemical kinetics was evaluated using dc polarization and ac impedance analysis techniques, and it was found that both diffusion and charge transfer of hydrogen play a role in electrolytic absorption of hydrogen. The hydrogen diffusivity in the alloys was estimated by an electrochemical method for fully charged alloy electrodes and was found to increase with increase in nickel content in the alloy.

Carbon assisted water electrolysis for hydrogen generation

Carbon Assisted Water Electrolysis (CAWE) is an energy efficient process in that H2 can be produced at lower applied voltage (∼1.0 V) compared to nearly 2.0 V needed for ordinary water electrolysis for the same H2 evolution rate. In this process, carbon is oxidized to oxides of carbon at the anode of an electrochemical cell and hydrogen is produced at the cathode. These gases are produced in relatively pure state and would be collected in a separate chamber. In this paper, we present the results of influence of various operating parameters on efficiency of CAWE process. The results showed that H2 can be produced at applied voltages Eo as low as 1.0V (vs. SHE) and its production rate is strongly dependent on the type of the carbon used and its concentration in the electrolyte. It has also been found that the performance of CAWE process is higher in acidic electrolyte than in alkaline electrolyte.