Lithium–sulfur batteries have great potential for high energy applications due to their high capacities,low cost and eco-friendliness. However, the particularly rapid capacity decay owing to the dissolution and diffu...Lithium–sulfur batteries have great potential for high energy applications due to their high capacities,low cost and eco-friendliness. However, the particularly rapid capacity decay owing to the dissolution and diffusion of polysulfide intermediate into the electrolyte still hamper their practical applications.And the reported preparation procedures to sulfur based cathode materials are often complex, and hence are rather difficult to produce at large scale. Here, we report a simple mechano-chemical sulfurization methodology in vacuum environment applying ball-milling method combined both the chemical and physical interaction for the one-pot synthesis of edge-sulfurized grapheme nanoplatelets with 3D porous foam structure as cathode materials. The optimal sample of 70%S–Gn Ps-48 h(ball-milled 48 h) obtains 13.2 wt% sulfur that chemically bonded onto the edge of Gn Ps. And the assembled batteries exhibit high initial discharge capacities of 1089 mAh/g at 0.1 C and 950 mAh/g at 0.5 C, and retain a stable discharge capacity of 776 mAh/g after 250 cycles at 0.5 C with a high Coulombic efficiency of over 98%. The excellent performance is mainly attributed to the mechano-chemical interaction between sulfur and grapheme nanoplatelets. This definitely triggers the currently extensive research in lithium–sulfur battery area.展开更多
Boosting the utilization efficiency of sulfur electrodes and suppressing the“shuttle effect”of intermediate polysulfides remain the critical challenge for high-performance lithium-sulfur batteries(LSBs).However,most...Boosting the utilization efficiency of sulfur electrodes and suppressing the“shuttle effect”of intermediate polysulfides remain the critical challenge for high-performance lithium-sulfur batteries(LSBs).However,most of reported sulfur electrodes are not competent to realize the fast conversion of polysulfides into insoluble lithium sulfides when applied with high sulfur loading,as well as to mitigate the more serious shuttle effect of polysulfides,especially when worked at an elevated temperature.Herein,we reported a unique structural engineering strategy of crafting a unique hierarchical multifunctional electrode architecture constructed by rooting MOF-derived CoS2/carbon nanoleaf arrays(CoS2-CNA)into a nitrogen-rich 3D conductive scaffold(CTNF@CoS2-CNA)for LSBs.An accelerated electrocatalytic effect and improved polysulfide redox kinetics arising from CoS2-CNA were investigated.Besides,the strong capillarity effect and chemisorption of CTNF@CoS2-CNA to polysulfides enable high loading and efficient utilization of sulfur,thus leading to high-performance LIBs performed not only at room temperature but also up to an elevated temperature(55°C).Even with the ultrahigh sulfur loading of 7.19 mg cm?2,the CTNF@CoS2-CNA/S cathode still exhibits high rate capacity at 55°C.展开更多
基金the Link Project of the National Natural Science Foundation of China and Guangdong Province(Grant no.U1301244)the National Natural Science Foundation of China(Grant nos.51573215,21506260)+2 种基金Guangdong Province Science&Technology Foundation(2011B050300008)Guangdong Natural Science Foundation(Grant nos.2014A030313159,2016A030313354)Guangzhou Scientific and Technological Planning Project(2014J4500002,201607010042)for financial support of this work
文摘Lithium–sulfur batteries have great potential for high energy applications due to their high capacities,low cost and eco-friendliness. However, the particularly rapid capacity decay owing to the dissolution and diffusion of polysulfide intermediate into the electrolyte still hamper their practical applications.And the reported preparation procedures to sulfur based cathode materials are often complex, and hence are rather difficult to produce at large scale. Here, we report a simple mechano-chemical sulfurization methodology in vacuum environment applying ball-milling method combined both the chemical and physical interaction for the one-pot synthesis of edge-sulfurized grapheme nanoplatelets with 3D porous foam structure as cathode materials. The optimal sample of 70%S–Gn Ps-48 h(ball-milled 48 h) obtains 13.2 wt% sulfur that chemically bonded onto the edge of Gn Ps. And the assembled batteries exhibit high initial discharge capacities of 1089 mAh/g at 0.1 C and 950 mAh/g at 0.5 C, and retain a stable discharge capacity of 776 mAh/g after 250 cycles at 0.5 C with a high Coulombic efficiency of over 98%. The excellent performance is mainly attributed to the mechano-chemical interaction between sulfur and grapheme nanoplatelets. This definitely triggers the currently extensive research in lithium–sulfur battery area.
基金financial support from the National Key Research and Development Program of China(2018YFB0104201).
文摘Boosting the utilization efficiency of sulfur electrodes and suppressing the“shuttle effect”of intermediate polysulfides remain the critical challenge for high-performance lithium-sulfur batteries(LSBs).However,most of reported sulfur electrodes are not competent to realize the fast conversion of polysulfides into insoluble lithium sulfides when applied with high sulfur loading,as well as to mitigate the more serious shuttle effect of polysulfides,especially when worked at an elevated temperature.Herein,we reported a unique structural engineering strategy of crafting a unique hierarchical multifunctional electrode architecture constructed by rooting MOF-derived CoS2/carbon nanoleaf arrays(CoS2-CNA)into a nitrogen-rich 3D conductive scaffold(CTNF@CoS2-CNA)for LSBs.An accelerated electrocatalytic effect and improved polysulfide redox kinetics arising from CoS2-CNA were investigated.Besides,the strong capillarity effect and chemisorption of CTNF@CoS2-CNA to polysulfides enable high loading and efficient utilization of sulfur,thus leading to high-performance LIBs performed not only at room temperature but also up to an elevated temperature(55°C).Even with the ultrahigh sulfur loading of 7.19 mg cm?2,the CTNF@CoS2-CNA/S cathode still exhibits high rate capacity at 55°C.
