Synthesis and Characterization of Na3SbS4 Solid Electrolytes via Mechanochemical and Sintered Solid-State Reactions: A Comparative Study

A sulfide-based solid electrolyte is an enticing non-organic solid-state electrolyte developed under ambient conditions. Na3SbS4, a profoundly enduring substance capable of withstanding exceedingly elevated temperatures and pressures, emerges as a focal point. Within this investigation, we employ dual distinct techniques to fabricate Na3SbS4, encompassing ball milling and the combination of ball milling with sintering procedures. A remarkable ionic conductivity of 3.1 × 10−4 S/cm at room temperature (RT), coupled with a meager activation energy of 0.21 eV, is achieved through a bifurcated process, which is attributed to the presence of tetragonal Na3SbS4 (t-NSS). Furthermore, we delve into the electrochemical performance and cyclic longevity of the Na2/3Fe1/2Mn1/2O2|t-NSS|Na system within ambient environs. It reveals 160 mAh/g initial charge and 106 mAh/g discharge capacities at 0.01 A/g current density. Furthermore, a cycle life test conducted at 0.01 A/g over 30 cycles demonstrates stable and reliable performance. The capacity retention further highlights its enduring energy storage capabilities. This study underscores the sustainable potential of Na3SbS4 as a solid-state electrolyte for advanced energy storage systems.