Targeting the dissolution of polyselenides: an investigation involving UV–vis spectroscopy and interlayer development

Official URL: https://dx.doi.org/10.1002/ente.202401187

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.