An extremely high rate Li–S battery with hybrid electrolyte

Polysulfide shuttling and lithium dendrites are two major issues which hinder the development of high-performance Li–S batteries. An ideal solution is to employ hybrid electrolyte consisting of sulfide solid electrolyte (SSE) and liquid electrolyte (LE), where SSE functions as a barrier for suppressing polysulfide shuttling and lithium dendrite growth while LE works as fast Li+ transport media. In this work, Li10SnP2S12 membranes, with a ceramic-like dense structure, provide a rigid barrier for preventing polysulfide shuttling and lithium dendrite growth. Meanwhile, its high ionic conductivity of 3.33 × 10−3 S/cm (25 °C), accompanied with good wetting and Li+ transport abilities of LE, renders the hybrid electrolyte system an excellent Li+ dynamic property. Consequently, the Li–S batteries fabricated with this SSE-based hybrid electrolyte system can operate at an extremely high charge/discharge rate. At a rate of 5C (7.10 mA/cm2), the batteries show an initial discharge capacity of 659.4 mAh/g, maintain at 471.4 mAh/g and 413.3 mAh/g after 50 and 100 cycles，showing a capacity retention of 71.53% and 62.67%, respectively. It is also proposed that a competitive mechanism exists between the electrochemical reaction and side reaction during cycling, where the electrochemical reaction dominates at high rates. An extremely high rate Li–S battery is obtained with hybrid electrolyte of SSE-LE. [Display omitted] •Li10SnP2S12 has a ceramic-like dense structure and high ionic conductivity of 3.33 × 10−3 S/cm at 25 °C.•An extremely high rate Li–S battery（5C, 7.1 mA/cm2）is obtained with hybrid electrolyte.•A competitive mechanism exists between the parasitic reaction and electrochemical reaction which dominates at high rate.