The shuttle effect derived from diffusion of lithium polysulfides(LiPSs) and sluggish redox kinetic bring about poor cycling stability and low utilization of sulfur,which have always been the key challenging issues fo...The shuttle effect derived from diffusion of lithium polysulfides(LiPSs) and sluggish redox kinetic bring about poor cycling stability and low utilization of sulfur,which have always been the key challenging issues for the commercial application of lithium-sulfur(Li-S) batteries.Rational design of cathode materials to catalyze Li_(2)S dissociation/nucleation processes is an appealing and valid strategy to develop high-energy practical Li-S batteries.Herein,considering the synergistic effect of bidirectional catalysis on LiPSs conversion and enhanced chemical immobilization for LiPSs by heteroatom doping,Pt nanoparticles loaded on nitrogen-doped carbon spheres(Pt/NCS composites) were constructed as cathode materials.According to the dynamic evolution of Pt catalysts and sulfur species,Pt~0 and Pt^(2+) species were identified as active species for the accelerated dissociation and nucleation of Li_(2)S,respectively.Meanwhile,in-situ Raman results demonstrated the expedited conversion of sulfur species resulted from bidirectional catalysis of active Pt species,corresponding to boosted redox kinetics.Consequently,Pt/NCS cathode exhibited improved long-term cyclability with high initial capacity,along with enhanced rate capability.This work provides a facile approach to construct cathode materials with bidirectional catalysis on Li_(2)S dissociation/nucleation,and sheds light on a more global understanding of the catalytic mechanism of metal catalysts during LiPSs conversion.展开更多
基金the financial support provided by the National Natural Science Foundation of China (51932005, 22072164)the Liaoning Revitalization Talents Program (XLYC1807175)+3 种基金the Research Fund of Shenyang National Laboratory for Materials Sciencethe IMR Innovation Fund (2023PY10)the Natural Science Foundation of Liaoning Province (2023-BS-013)the Science and Technology Research Project of Education Department of Jilin Province (JJKH20210453KJ)。
文摘The shuttle effect derived from diffusion of lithium polysulfides(LiPSs) and sluggish redox kinetic bring about poor cycling stability and low utilization of sulfur,which have always been the key challenging issues for the commercial application of lithium-sulfur(Li-S) batteries.Rational design of cathode materials to catalyze Li_(2)S dissociation/nucleation processes is an appealing and valid strategy to develop high-energy practical Li-S batteries.Herein,considering the synergistic effect of bidirectional catalysis on LiPSs conversion and enhanced chemical immobilization for LiPSs by heteroatom doping,Pt nanoparticles loaded on nitrogen-doped carbon spheres(Pt/NCS composites) were constructed as cathode materials.According to the dynamic evolution of Pt catalysts and sulfur species,Pt~0 and Pt^(2+) species were identified as active species for the accelerated dissociation and nucleation of Li_(2)S,respectively.Meanwhile,in-situ Raman results demonstrated the expedited conversion of sulfur species resulted from bidirectional catalysis of active Pt species,corresponding to boosted redox kinetics.Consequently,Pt/NCS cathode exhibited improved long-term cyclability with high initial capacity,along with enhanced rate capability.This work provides a facile approach to construct cathode materials with bidirectional catalysis on Li_(2)S dissociation/nucleation,and sheds light on a more global understanding of the catalytic mechanism of metal catalysts during LiPSs conversion.
