Targeting the Dissolution of Polyselenides: An Investigation Involving UV-Vis Spectroscopy and Interlayer Development

Abstract

Li-Se batteries are promising energy storage systems due to the high theoretical volumetric capacity and electrical conductivity of selenium. However, the formation of dissolved polyselenide in ether-based electrolytes is one of the main factors affecting the electrochemical performance of Li-Se batteries. Herein, the presence and solubility of polyselenides in ether-based electrolytes are initially investigated using UV-vis spectroscopy and compared with carbonate-based solvents. Then, to address the polyselenide shuttle effect, SnCl2-containing poly(acrylonitrile-co-vinylpyrrolidone) (oPANVP/SnCl2) nanofibrous interlayer is utilized to retain the dissolved compounds. The absorption capacity of this interlayer is investigated and quantitatively demonstrated by UV-vis spectroscopy. The cell with the interlayer achieves a discharge capacity of 266 mAh g-1 after 150 cycles, significantly higher than the cell without the interlayer. Furthermore, 3-electrode electrochemical impedance spectroscopy and open-circuit voltage monitoring are conducted to investigate the impact of the oPANVP/SnCl2 interlayer on the solubility of polyselenides. The improved electrochemical results indicate that ether-based electrolytes can be successfully utilized in Li-Se batteries when an effective interlayer is present to adsorb polyselenides. The existence and solubility of polyselenides in both ether-based and carbonate-based electrolytes are investigated by UV-vis spectroscopy. SnCl2-containing poly(acrylonitrile-co-vinylpyrrolidone) (oPANVP/SnCl2) nanofibrous interlayer is used to alleviate the polyselenide shuttle effect in ether-based electrolytes. The absorption capacity of this interlayer is examined and quantitatively shown by UV-vis spectroscopy.image (c) 2024 WILEY-VCH GmbH