Inhibiting Polysulfide Shuttle in Lithium–Sulfur Batteries through Low‐Ion‐Pairing Salts and a Triflamide Solvent. Issue 22 (2nd May 2017)

• Record Type: Journal Article
• Authors: Shyamsunder, Abhinandan; Beichel, Witali; Klose, Petra; Pang, Quan; Scherer, Harald; Hoffmann, Anke; Murphy, Graham K.; Krossing, Ingo; Nazar, Linda F.
• Is Part Of: Angewandte Chemie international edition. Volume 56:Issue 22(2017)
• Page Start: 6192
• Page End: 6197
• Publication Date: 2017-05-02
• Subjects: lithium–sulfur batteries -- low ion-pairing salts -- polysulfide shuttle -- sparingly solvating electrolyte -- sulfonamide; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201701026
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The step‐change in gravimetric energy density needed for electrochemical energy storage devices to power unmanned autonomous vehicles, electric vehicles, and enable low‐cost clean grid storage is unlikely to be provided by conventional lithium ion batteries. Lithium–sulfur batteries comprising lightweight elements provide a promising alternative, but the associated polysulfide shuttle in typical ether‐based electrolytes generates loss in capacity and low coulombic efficiency. The first new electrolyte based on a unique combination of a relatively hydrophobic sulfonamide solvent and a low ion‐pairing salt, which inhibits the polysulfide shuttle, is presented. This system behaves as a sparingly solvating electrolyte at slightly elevated temperatures, where it sustains reversible capacities as high as 1200–1500 mAh g −1 over a wide range of current density (2C–C/5, respectively) when paired with a lithium metal anode, with a coulombic efficiency of >99.7 % in the absence of LiNO3 additive. Abstract : The detrimental polysulfide shuttle associated with Li‐S batteries is alleviated (without the addition of LiNO3 ) through the combined use of a non‐polar sulfonamide solvent and low‐ion‐pairing salt as the electrolyte. This combination transforms to a sparingly solvating electrolyte at 50 °C and sustains close to theoretical capacity at rates of C/5 with a coulombic efficiency of 99.7 %.