All-Solid-State Na/S Batteries with a Na3PS4 Electrolyte Operating at Room Temperature

作者：Tanibata Naoto; Deguchi Minako; Hayashi Akitoshi^*; Tatsumisago Masahiro^*

来源：Chemistry of Materials, 2017, 29(12): 5232-5238.

DOI：10.1021/acs.chemmater.7b01116

Bulk-type all-solid-state Na/S cells, which are expected to have high capacity, be highly safe, and have low material cost, were fabricated using a Na3PS4 glass-ceramic as a solid electrolyte. The sulfur composite electrodes were prepared by mechanical milling of sulfur active material, a conductive additive (acetylene black), and a Na3PS4 glass-ceramic electrolyte. The all solid -state Na/S cells used the reaction up to the final discharge product of sulfur active material, Na2S, and achieved a high capacity of similar to 1100 mAh (g of S)(-1) at room temperature. The rate of utilization of sulfur active material was similar to 2 times higher than that of high-temperature-operating NAS batteries (commercially available NAS batteries, Na/sintered beta ''-alumina/S), where Na2Sx melts with bridging sulfurs contribute to redox in the sulfur electrodes. The open circuit potential curve of the discharge process of the Na/S batteries operating at room temperature was similar to that of the NAS batteries operating at high temperatures; X-ray diffraction and Xray photoelectron spectroscopy measurement indicated that amorphous Na2Sx with a structure similar to the structure of these melts contributed to sulfur redox reaction in the all-solid-state Na/S cells. A galvanostatic intermittent titration technique and impedance measurement suggested that the overpotential during the discharge process in the all-solid-state Na/S cells was mainly derived from the sodium diffusion resistance in the solid sulfur active material. The finding would be an effective guide for achieving higher performance for all-solid-state Na/S cells.

• 出版日期2017-6-27