Improvement of Rate Performance for All-Solid-State Na15 Sn4/Amorphous TiS3 Cells Using 94Na3PS4•6Na4SiS4 Glass-Ceramic Electrolytes

Rate performance of all-solid-state sodium cells (Na15Sn4/Na3PS4 glass-ceramic/a-TiS3) was investigated. The resistance attributable to Nai5Sn4 negative electrode was increased with the discharge-charge cycles. The addition of acetylene-black (AB) to the Na15Sn4 electrode suppressed the resistance increase and improved the rate performance; eg. the capacity at the current density of 0.13 MA cm(-2) increased from ca. 65 mAh g(-1) to ca. 175 mAh g(-1). In addition, the replacement of Na3PS4 glass-ceramic by 94Na(3)PS(4) 6Na(4)SiS(4) (mol%) glass-ceramic with a higher sodium ion conductivity decreased the cell resistance related to solid electrolyte (separator and positive electrode) and thus increased the cell capacity from ca. 36 mAh CI to ca. 185 mAh g(-1) at the current density of 0.25 mA cm(-2). (C) 2015 The Electrochemical Society. All rights reserved.