A PEFC that utilizes a borohydride compound, usually sodium borohydride in aqueous alkaline medium, directly as a fuel is termed as direct borohydride fuel cell (DBFC). A DBFC is a device that converts chemical energy stored in borohydride ion ( ) and an oxidant directly into electricity by redox processes. Usually, a DBFC employs an alkaline solution of sodium borohydride (NaBH 4 ) as fuel and oxygen as oxidant. DBFC has some attractive features such as high open circuit potential, low operational temperature and high power density. The DBFC is a promising power system for portable applications. Sodium borohydride (NaBH4), which has a capacity value of 5.67 Ah g -1 and hydrogen content of 10.6 wt.%, is a good alternative to methanol and hydrogen as a fuel. In the recent years, extensive research work is being carried out and reported on improving the performance of nanocatalysts for both anode and cathode of fuel cells. In this thesis the single cell performance of carbon supported non-platinum electrocatalyst (Hypermec TM K 14 ) as cathode material was investigated in alkaline electrolyte borohydride fuel cells and compared to that of 10% Pt/C (commercial). The structural and electrochemical aspects of the Hypermec TM K 14 and 10% Pt/C (commercial) electrocatalysts were further investigated. X-ray diffraction (XRD) indicates the Pt and K 14 particles average size is lesser than 20 nm. Scanning electron microscopy (SEM) shows the spherical shape of Pt and K 14 particles and distributed homogeneously across the substrate matrix. The Hypermec TM K 14 cathode showed superior performance to that observed using the 10% Pt/C cathode, e.g. power density up to 138 mWcm -2 . Cyclic voltammetry data exhibit the better borohydride tolerance for K 14 and Electrochemical impedance spectroscopy (EIS) analyses demonstrated that the cell with K 14 nanocatalyst showed not only low ohmic resistance but also small charge and mass transfer resistances. The difference in performance can be attributed to variations in activity towards oxygen reduction reaction and in borohydride tolerance among the cathodes.
