(689g) UV Cured Polymer Electrolyte for Solid State Lithium Sulfur Batteries

Lithium sulfur batteries (LiS) are heralded as the next generation of high energy battery systems due to their high theoretical specific capacity of 1675 mAh/g. Lithium sulfur batteries suffer from a loss of active sulfur which emanate from the dissolution of intermediate lithium polysulfide species during the redox reaction, resulting in diminution of cycle life. To mitigate this issue, we developed a UV cured, ionically conductive, poly (ethylene glycol) diacrylate (PEGDA) based solid polymer electrolyte. However, polymer electrolytes are plagued with a demonstratively low room temperature ionic conductivity; thus, the effects of nanoparticle fillers (silicon, silicate and silicon carbide) on the electrochemical performance were investigated. X-Ray Diffraction (XRD) was used to study the effect of the added fillers on the crystallinity of the electrolyte membrane, while Scanning Electron Microscopy (SEM) was used to understand the distribution of filler materials into the framework of the electrolyte. To gauge the electrolyte’s ionic conductivity, electrochemical impedance spectroscopy (EIS) was utilized in lithium-ion blocking symmetrical cells format. Cycle life and electrochemical performance was evaluated through construction of LiS cells with a novel CoS cathode endowed with a high loading of sulfur and a lithium metal anode. Through the incorporation of lithium salt into the succinonitrile cross-linked molecules of the polymer, the electrolyte is able to deliver a room temperature, specific capacity of 296 mAh/g with improved cycle life. This study will provide a better understanding of the effects of nanoparticle fillers with PEGDA electrolytes on the energy density and cycling stability in solid state Li-S batteries.