Polysulfide-Permanganate Flow Battery Using Abundant Active Materials

A new flow battery is presented using the abundant and inexpensive active material pairs permanganate/manganate disulfide/tetrasulfide. wetted set identified for compatibility with strongly oxidizing manganese couple at ambient elevated temperatures. Both solutions allow high solubility, cells tested theoretical energy densities up to 43 Wh l ?1 ?1.2 V cell. Full built nickel foam electrodes sodium-exchanged Nafion 115 membranes deliver a baseline area-specific resistance of 2.7 ?-cm 2 . Incorporation high-surface-area cobalt-coated carbon paper stainless steel mesh electrodes, an expanded membrane delivers 44% lower 1.6 All show performance decay over course cycling. The Co-decorated provide significant kinetic improvements, shifting electrode from non-linear Ni-foam linear volume-normalized exchange current density value 3.2 cm ?3 provides increased conductivity 13 mS observed in as-received, 115. Although boiled improved conductivity, it cost decreased Coulombic efficiency poorer manufacturability. cell models suggest that similar resistances (1.7 ) should be feasible as-received advanced electrodes.