Stabilization of Cubic-Na3PS4 to Enhance Ionic Conductivity of Solid Electrolytes for All-Solid-State Sodium Sulfur Batteries

Solid-state electrolytes (SSE’s) are crucial in realizing the potential of novel rechargeable batteries. All-solid-state batteries with inorganic solid electrolytes offer a number of advantages by improving safety, reliability, and cost [1]. Sulfide glasses are promising as a solid electrolyte due to their superionic ionic conductivity [3]. Na 3 PS 4 is a glass-ceramic that is precipitated from the sulfide glass matrix, exhibiting ionic conductivities of 10 -6 and 10 -4 S/cm for the tetragonal and cubic phases, respectively [4]. Here we provide a simple synthesis process for stabilizing the cubic phase, which also reduces the activation energy to 330 meV. We also investigate anion doping, which can further improve upon this result by increasing Na vacancies, via a composition curve of Cl-doping to determine optimal concentration of (1-x)Na 3 PS 4 -xNaCl, for 0 > x > 0.0625. Acknowledgements This work was supported by National Science Foundation under grant number ACI-1053575. References [1] Kamaya, Noriaki et al. “A Lithium Superionic Conductor.” Nature Materials 10.9 (2011): 682–686. Web. [2] Hayashi, Akitoshi et al. “Superionic Glass-Ceramic Electrolytes for Room-Temperature Rechargeable Sodium Batteries.” Nature Communications 3.May (2012): 856. Web.Tatsumisago, Masahiro, and Akitoshi Hayashi. “Sulfide Glass-Ceramic Electrolytes for All-Solid-State Lithium and Sodium Batteries.” International Journal of Applied Glass Science 10 (2014): 226–235. Web. [3] Ribes, M., B. Barrau, and J.L Souquet. “Sulfide Glasses: Glass Forming Region, Structure and Ionic Conduction of Glasses in Na2S-XS2 (X=Si, Ge), Na2S-P2S5, and Li2SGeS2 Systems.” Journal of Non-Crystalline Solids 39 (1980): 271–276. Print. [4] Hayashi, Akitoshi et al. “Superionic Glass-Ceramic Electrolytes for Room-Temperature Rechargeable Sodium Batteries.” Nature Communications 3.May (2012): 856. Web. Figure 1