Study of a high power density sodium polysulfide/bromine energy storage cell

Abstract

Nickel catalyst supported on carbon was made by reduction of nickelous nitrate with hydrogen at high temperature. Ni/C catalyst characterization was carried out by XRD. It was found that the crystal phase of NiS and NiS 2 appeared in the impregnated catalyst. Ni/C and Pt/C catalysts gave high performance as the positive and negative electrodes of a sodium polysulfide/bromine energy storage cell, respectively. The overpotentials of the positive and negative electrodes were investigated. The effect of the electrocatalyst loading and operating temperature on the charge and discharge performance of the cell was investigated. A power density of up to 0.64 W cm À2 (V ¼ 1.07 V) was obtained in this energy storage cell. A cell potential efficiency of up to 88.2% was obtained when both charge and discharge current densities were 0.1 A cm À2 .

Fundamental models for flow batteries

“…The ZneCe redox flow battery is a system that combines the very negative zinc couple with a very positive cerium couple to yield an open-circuit voltage that is higher than any of its commercial competitors [40]. It has been under development since the early 1990s by Electrochemical Design Associates Inc [41].…”

Characteristics and performance of 10kW class all-vanadium redox-flow battery stack

“…Different kinds of RFBs have been studied at our research group since 1989 [3,[17][18][19][20][21][22][23][24][25][26]. In this work, we focused on the characteristics and performance of the VRB cell stack recently developed in our lab.…”

Correlating Microstructure and Activity for Polysulfide Reduction and Oxidation at WS2Electrocatalysts

“…This suggests that the polarization of the milled WS 2 is not influenced by mass transport. Table III summarizes the Tafel parameters evaluated from the potentiostatic steady state polarization data shown in Figure 14, fitted to the exponential approximation of the Butler-Volmer equation: 79 i SS = i 0 10 ±η/b [7] where i SS is the steady state current, i 0 is the exchange current density. b is the Tafel slope, and η is the overpotential.…”

“…The linearity of the simulated kinetic polarization plots of Figure 20 indicate that a single kinetic regime prevails for polysulfide reduction and a single kinetic regime prevails for polysulfide oxidation Mass transport and anodic passivation.-Several authors have observed the 'passivation' of their electrodes during polysulfide oxidation due to the formation of a S film. [7][8][9]29,[107][108][109] Zhou et al propose that efficient mass transport can prevent this anodic passivation. 9 Presumably, mass transport alleviates the passivation as a result of the autocatalytic effect that polysulfides seem to exhibit upon the dissolution of the S layer.…”

“…The polysulfide bromine redox flow battery could represent a viable solution for the storage of energy on a large scale. [5][6][7][8][9] Through the following reaction, electrical energy is stored in chemical bonds: xNa 2 S x+1 + 3NaBr → (x + 1) Na 2 S x + NaBr 3 [1] Upon charging, sodium tribromide is oxidized at the anode: 3NaBr → NaBr 3 + 2Na + + 2e − [2] The sodium polysulfide species are reduced to lower polysulfide species at the cathode: xNa 2 S x+1 + 2Na + + 2e − → (x + 1)Na 2 S x [3] where (1 ≤ x ≤ 4). Alternatively, only taking into consideration the most abundant species in solution (the other species are in equilibrium with these species), the polysulfide reaction can be depicted as: 10…”