Room Temperature Sulfur Cathode Design and Processing Techniques

Abstract

As energy demand steadily increases, sulfur battery chemistries gain more and more attention for their promise to enable long-duration portable energy (Li-S system) and extremely low cost stationary storage for incorporation of renewables (Na-S system). The Li-S battery, which converts metallic lithium and elemental sulfur to lithium sulfide (Li2S) reversibly at the cathode, promises 6X the energy storage of the conventional Li-ion battery. This dissertation enables high performance Li-S cathodes by mitigating poor electrical conductivity and solubility of active materials with careful nanomaterial design. Further, this work champions dramatically improved sulfur composite processing technique using low temperature (175°C), isothermal vapor, which facilitates optimal performance of the nanomaterial electrode designs. This process also boasts enhanced scalability over the conventional melt infiltration with 60X throughput at the same low temperature. By pushing the limits of the isothermal vapor infiltration technique, this work demonstrates one of the first highly stable, low-cost room temperature Na-S cathodes. This electrode, developed from table sugar, provides significant hope for, grid storage, competitive in price with burning natural gas, to allow penetration of renewable resources into the grid by load leveling weather related intermittencies.