Efficient suppression of the shuttle effect in Na–S batteries with an As2S3 anchoring monolayer

Abstract

Sodium–sulfur batteries (NaSBs) have emerged as a promising energy storage technology for large-scale stationary applications such as smart electrical grids due to their exceptionally high energy density and cost-effectiveness. However, one of the challenging problems impeding their practical applications is the sulfur shuttle effect by which the active redox intermediates are gradually dissolved in electrolytes. In this work, we have employed first-principles density functional theory (DFT) calculations to unravel the suppression of the shuttle effect in NaSBs with a two-dimensional (2D) As₂S₃ monolayer as the anchoring material. We show that semiconducting As₂S₃ is a suitable anchoring layer to inhibit the dissolution of the polysulfide intermediates in common electrolytes because of its stronger chemical binding with sodium polysulfides than with the electrolytes. The immense adsorption is attributed to the electron donation from the unfilled S-3p states of the polysulfides to As₂S₃. These mechanisms increase the carrier population and consequently improve the electrical conductivity of As₂S₃. Hence, the use of As₂S₃ can both reduce the shuttle effect and enhance the cathode electron conductivity to enable improved cycling stability and coulombic efficiency of the battery.