Water flow batteries (RFBs) are a large-scale long-term energy storage technology with intrinsic safety properties, which utilize the electrochemical oxidation-reduction reaction of active substances to achieve the storage and conversion between chemical energy and electrical energy. The water-based polysulfide flow battery has become a new flow battery technology route with large-scale application prospects due to its high abundance, low cost, high solubility, and multi electron transfer ability. However, the slow electrochemical kinetics of polysulfides can significantly exacerbate polarization phenomena, leading to a decrease in energy efficiency and cycle life.
Based on this, Professor Chen Jiajia's research group has designed a two-dimensional ordered mesoporous nitrogen doped carbon composite molybdenum disulfide with a sandwich shaped nanostructure（ Meso-NC@MoS2 ）Heterojunction is used to promote the adsorption of polysulfides and accelerate their slow kinetics. Theoretical calculations confirm that the directional electron transport channel established between MoS2 and Meso NC accelerates the electron transfer from Meso-NC@MoS2 The transfer to S42- effectively promotes the dissociation of S42- and the formation of low order polysulfides. Basic electrochemical tests indicate that Meso-NC@MoS2 On the electrode, the aqueous polysulfides exhibited the maximum reaction kinetics activity (with a 3.2-fold increase in reaction rate constant) and the minimum peak potential difference (with a decrease in Δ Ep to 0.21 V), highlighting outstanding catalytic activity and reaction reversibility. Compared to pure carbon felt electrodes, based on Meso-NC@MoS2 The overpotential of the water-based polysulfide flow battery significantly decreased by about 377 mV during charging, and effectively weakened the polarization of the battery. After running continuously for 3200 cycles within 30 days, the battery still maintains a peak power density of 112 mW cm-2 and a Coulombic efficiency of 99.9%.
This work was completed under the guidance of Professor Chen Jiajia. The 2020 doctoral student Lan Jinji, 2023 doctoral student Zhang Shu, and Associate Professor Yang Le from Southwest University are the co first authors of the paper. Master's students Chen Chunjun and Wu Huilei, as well as engineers Feng Liubin and An Dongli, participated in some research work, which was supported by the National Natural Science Foundation of China (22441030, 22393901, 22021001, 22272143), the National Key Research and Development Program (2021YFA1502300), the Basic Research Funds for Central Universities (20720250005), the National Key Laboratory of Surface and Interface Chemistry, and the Natural Science Foundation of Fujian Province (2024J01213135).