High performance room temperature all-solid-state Na-SexS battery with Na3SbS4-coated cathode via aqueous solution

All-solid-state(ASS)Na-S batteries are promising for large-scale energy storage because of the incombustible solid electrolyte and avoiding the dissolution of intermediates.However,the poor contact between the active material and the solid electrolyte in the positive electrode leads to poor electrochemical performance.Here,we report an aqueous solution approach to fabricate Na3SbS4-coated SexS-based active materials for a Na-S battery working at room temperature.Compared with the Na3SbS4 and SexS mixed cathode,the coated cathode achieves significantly improved Na-ion diffusion kinetics and reduced impedance resistance.Additionally,the nanoparticle coating sustains the volume expansion of the cathode during cycling.The resulting batteries deliver an intensively enhanced specific capacity at various rates.Regardless of the mass loading,the Na3SbS4-coated cathode maintains a decent reversible capacity for the long-term discharge/charge cycling.The best battery achieves an initial discharge capacity of509 mAh g^-1 at a current density of 437.4 mA g^-1 and capacity retention of 98.9%for 100 cycles.To the best of our knowledge,this is one of the best room temperature ASS Na-S battery so far.This work demonstrates that Na3SbS4 is very promising for the cathode coating purpose for ASS Na-S batteries.

Stabilizing Na_(3)SbS_(4)/Na interface by rational design via Cl doping and aqueous processing

Solution-synthesis method is attractive for solid electrolytes because it is a facile and scalable process to be used to permeate electrodes and to construct a thin electrolyte coating layer on active materials.In this work,we report Cl-doped Na_(3)SbS_(4) prepared via aqueous-solution approach.Besides decent ionic conductivity,the aqueous-solution approached electrolyte demonstrates an improved interfacial stability toward Na metal compared to the solid-state sintered one because of the residual hydrate,nanosized microstructure,and Cl incorporation.All-solid-state batteries using the solution-prepared electrolytes have enhanced cycling performance,though the performance still needs to be further improved.