Performance of 2,4-dinitrophenol as a positive electrode in magnesium reserve batteries

Magnesium is an interesting anode battery material with many advantages such as its high standard potential of (−2.37 V), low cost and good low-temperature performance due to an exothermic corrosion reaction during discharge. Organic aromatic nitro compounds undergo multi-electron transfers of up to 18 during discharge, and hence, give high specific energies (up to 2 A h/g) in comparison with conventional inorganic battery depolarizers such as MnO2, HgO, CuO and AgO. Thus, it is worthwhile fabricating and studying the performance of a battery system combining magnesium and 2,4-dinitrophenol (DNP) using aqueous halide electrolytes like MgCl2, MgBr2 and Mg(ClO4)2.This paper describes the preparation of DNP cathodes after standardization of the cathode mixture. Mg/DNP cells (1 V, 1 A h) have been assembled using the above cathode in conjunction with magnesium alloy (AZ 31) anodes and discharged at different current densities (1.7, 3.3, 5, 6.6 mA/cm2) in 2 M MgCl2, MgBr2 and Mg(Cl04)2. Cyclic voltammograms of DNP have been recorded in 2 M Mg(ClO4)2 at various sweep rates and concentrations in order to understand the reduction behavior. The study suggests that DNP is a suitable organic compound for use as a positive electrode material in magnesium reserve batteries.