Diogo Santos

Abstract:

Typical fuel cells use hydrogen (H2) as the fuel and oxygen (O2) as the oxidant. However, safety issues and the high costs involved in gas storage in pressurised containers are leading many researchers to drive their focus to liquid-feed fuel cells. One option is the direct borohydride fuel cell (DBFC). Basically, the DBFC is an electrochemical device that converts the chemical energy contained in a sodium borohydride (NaBH4) alkaline solution directly into electric energy. While the NaBH4 fuel is oxidised at the anode, oxygen (O2) or hydrogen peroxide (H2O2) oxidants are reduced at the cathode. The use of liquid reactants makes the DBFC a promising solution for space, underwater, and specific terrestrial applications where O2 is not available. Most of the current research on the DBFC is focused on the development of inexpensive electrocatalysts that are able to efficiently catalyse the fuel cell reactions.
Like having flashbacks from the past, herein we briefly review the main studies that we have carried out in the last 10 years in the development of electrocatalytic materials for application in DBFCs, both for NaBH4 oxidation and for O2/H2O2 reduction. The advantages of high energy density and room temperature operation suggest future use of the DBFC for portable applications.