Comprehensive investigation on sodium hypochlorite as oxidant in half cell and direct sodium borohydride fuel cell (DSBFC) for low-cost electrical power generation

Abstract

The electrochemical reduction of sodium hypochlorite in alkaline medium was thoroughly studied on commercial cathode Pt(40 wt.%)/CHSA electrocatalyst to enhance the performance of a DSBFC. The cyclic voltammetry (CV) study and chronoamperometry (CA) tests using PGSTAT 204, Autolab Netherland, were carried out in a three-electrode half-cell setup to investigate the electrochemical behaviour of oxidant NaOCl in alkaline medium. The effect of various parameters such as oxidant NaOCl concentration, electrolyte (NaOH) concentration and cathode electrocatalyst loading was thoroughly studied and optimized using CV in half-cell and single-cell configuration. The optimum values of oxidant/NaOCl concentration, electrolyte/NaOH concentration and cathode electrocatalyst loading were found to be 2 M, 1 M and 2 mg/cm2, respectively, in half-cell CV analysis. The single-DSBFC study was also performed to validate the optimum values of the effective parameters which were found to be the same as that of the half-cell study. In the single-DSBFC study, the maximum power density of 58.80 mW/cm2 at the current density of 112 mA/cm2 was achieved at the cell temperature of 30 °C, whereas the maximum power density of 69.44 mW/cm2 at the current density of 160 mA/cm2 was achieved at the cell temperature of 60 °C. The power density of DSBFC increased by 18.09% when the cell temperature was raised from 30 to 60 °C. Graphical Abstract: (Figure presented.) © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.