The effect of V2O5/C additive on the suppression of polysulfide dissolution in Li-sulfur batteries

Abstract

The effect of adding a V2O5/carbon nano-composite to the cathode of a Li-sulfur battery on suppressing the polysulfide dissolution phenomenon was evaluated by comparing the amount of overcharge at the first discharge-charge processes. V2O5/carbon nano-composite was manufactured by forming V2O5 a <...H2O xerogel on the carbon black through a simple wet process. This provides a high surface area with plenty of hydrophilic moieties that can capture and store soluble polysulfides on its surface during the discharge-charge reactions, and also partly contributes to suppressing the excessive formation of Li2S which undergoes a large volume change during the cycling. From the electrochemical results, we could observe a significant reduction in the overcharge amount and improved cyclic performance by adding as little as 2 % of the nano-composite. UV-VIS spectra measured after a small addition of the nano-composite to the solution containing Li2S6 polysulfide also confirmed that the V2O5/carbon nano-composite is highly effective in capturing long-chain polysulfides on its surface.