Towards safe lithium-sulfur batteries from liquid-state electrolyte to solid-state electrolyte

Lithium-sulfur(Li-S)battery has been considered as one of the most promising future batteries owing to the high theoretical energy density(2600 W-h-kg-1)and the usage of the inexpensive active materials(elemental sulfur).The recent progress in fundamental research and engineering of the Li-S battery,involved in electrode,electrolyte,membrane,binder,and current collector,has greatly promoted the performance of Li s batteries from the laboratory level to the approaching practical level.However,the safety concerns still deserve attention in the following application stage.This review focuses on the development of the electrolyte for Li S batteries from liquid state to solid state.Some problems and the corresponding solutions are emphasized,such as the soluble lithium polysulfides migration,ionic conductivity of electrolyte,the interface contact between electrolyte and electrode,and the reaction kinetics.Moreover,future perspectives of the safe and high-performance Li S batteries arealso introduced.

An integrated approach to configure rGO/VS_(4)/S composites with improved catalysis of polysulfides for advanced lithium-sulfur batteries

Lithium-sulfur(Li-S)battery is labeled as a promising high-energy-density battery system,but some inherent drawbacks of sulfur cathode materials using relatively complicated techniques impair the practical applications.Herein,an integrated approach is proposed to fabricate the high-performance rGO/VS_(4)/S cathode composites through a simple one-step solvothermal method,where nano sulfur and VS_(4) particles are uniformly distributed on the conductive rGO matrix.rGO and sulfiphilic VS_(4)provide electron transfer skeleton and physical/chemical anchor for soluble lithium polysulfides(LiPS).Meanwhile,VS_(4) could also act as an electrochemical mediator to efficiently enhance the utilization and reversible conversion of LiPS.Correspondingly,the rGO/VS_(4)/S composites maintain a high reversible capacity of 969 mAh/g at 0.2 C after 100 cycles,with a capacity retention rate of 82.3%.The capacity fade rate could lower to 0.0374%per cycle at 1 C.Moreover,capacity still sustains 795 m Ah/g after 100 cycles in the relatively high-sulfurloading battery(6.5 mg/cm^(2)).Thus,the suggested method in configuring the sulfur-based composites is demonstrated a simple and efficient strategy to construct the high-performance Li-S batteries.