Sulfurized Polyacrylonitrile Solid State Lithium Batteries Using Gel Polymer Interlayers

Abstract

Solid state garnet electrolytes offer stability against lithium dendrite formation, relatively high ionic conductivity, and a wide electrochemical window. They also can block the lithium polysulfide shuttle effect in sulfur batteries. In combination with sulfur cathodes, garnet solid-state electrolytes can increase battery energy densities greatly. In this study, the addition of novel mixed ion electric conductors (MIEC) to solid state batteries is examined. In addition, a poly(vinylidene fluoride)-co-hexafluoropropylene (PVDF-HFP) gel polymer electrolyte is developed and characterized to stabilize the cathode garnet interface. The gel polymer electrolyte had stability up to 4.8V. A lithium conductivity of 5.28x10-5 Scm-1 and the transference number of 0.103 was calculated. Full cells were constructed with lithium metal and sulfurized polyacrylonitrile. Three different structures were tested. It was found that the addition of MIEC helped create long lasting cells with 80% capacity retention after 303 cycles.