Lithium-sulfur batteries(LSBs)offer high energy density and low cost but face challenges such as low sulfur utilization,lithium polysulfides(LiPSs)shuttling,and limited reaction kinetics.To address these issues,we rat...Lithium-sulfur batteries(LSBs)offer high energy density and low cost but face challenges such as low sulfur utilization,lithium polysulfides(LiPSs)shuttling,and limited reaction kinetics.To address these issues,we rationally design a Ti_(3)C_(2)T_(x)/SnS Mott-Schottky heterostructure with a built-in electric field.This three-dimensional(3D)porous architecture can enhance sulfur loading,facilitate electrolyte penetration,and expose more adsorption and catalytic sites.More importantly,the built-in electric field facilitates charge transfer and directs LiPSs migration from SnS to Ti_(3)C_(2)T_(x).The oriented migration of LiPSs enables rapid catalytic conversion at the Ti_(3)C_(2)T_(x)/SnS heterogeneous interface,enhancing electrocatalytic activity and sulfur reduction reaction kinetics.The Ti_(3)C_(2)T_(x)/SnS/S cathode achieves a high initial capacity(1367.1 mAh g^(-1)),excellent rate performance(602.7 mAh g^(-1)at 3 C),and stable long cycling performance with an average capacity decay rate of only 0.029%per cycle at 2 C.Additionally,a high-sulfur-loaded 3 Dprinted cathode with loading of 12.7 mg cm^(-2)manufactured using 3D printing exhibits an areal capacity of 15.0 mAh cm^(-2),retaining 8.9 mAh cm^(-2)after 70 cycles.展开更多
The stereoselective construction of vicinal all-carbon quaternary stereocenters has long been a formidable synthetic challenge.Direct asymmetric coupling of a tertiary carbon nucleophile with a tertiary carbon electro...The stereoselective construction of vicinal all-carbon quaternary stereocenters has long been a formidable synthetic challenge.Direct asymmetric coupling of a tertiary carbon nucleophile with a tertiary carbon electrophile is themost straightforward approach,but it is sterically and energetically disfavored.Herein,we describe a catalytic asymmetric substitution,where racemic tertiary bromides coupled directly with racemic secondary or tertiary carbanion.展开更多
基金the financial support from the National Natural Science Foundation of China(52203340)the Guangdong Basic and Applied Basic Research Foundation(2025A1515012287)+1 种基金the Natural Science Foundation of Hubei Province(Joint Fund,2025AFD334)the Hubei Key Laboratory of Energy Storage and Power Battery(Hubei University of Automotive Technology,ZDK22024B06)。
文摘Lithium-sulfur batteries(LSBs)offer high energy density and low cost but face challenges such as low sulfur utilization,lithium polysulfides(LiPSs)shuttling,and limited reaction kinetics.To address these issues,we rationally design a Ti_(3)C_(2)T_(x)/SnS Mott-Schottky heterostructure with a built-in electric field.This three-dimensional(3D)porous architecture can enhance sulfur loading,facilitate electrolyte penetration,and expose more adsorption and catalytic sites.More importantly,the built-in electric field facilitates charge transfer and directs LiPSs migration from SnS to Ti_(3)C_(2)T_(x).The oriented migration of LiPSs enables rapid catalytic conversion at the Ti_(3)C_(2)T_(x)/SnS heterogeneous interface,enhancing electrocatalytic activity and sulfur reduction reaction kinetics.The Ti_(3)C_(2)T_(x)/SnS/S cathode achieves a high initial capacity(1367.1 mAh g^(-1)),excellent rate performance(602.7 mAh g^(-1)at 3 C),and stable long cycling performance with an average capacity decay rate of only 0.029%per cycle at 2 C.Additionally,a high-sulfur-loaded 3 Dprinted cathode with loading of 12.7 mg cm^(-2)manufactured using 3D printing exhibits an areal capacity of 15.0 mAh cm^(-2),retaining 8.9 mAh cm^(-2)after 70 cycles.
基金support from Nanyang Technological University for Tier 1 grants(RG1/19 and RG2/20)and Ministry of Education(Singapore)Tier 2 grants(no.MOE2019-T2-1-091)the University of Wollongong(VC Fellowship)and the Australian Research Council(DECRA DE210100053).
文摘The stereoselective construction of vicinal all-carbon quaternary stereocenters has long been a formidable synthetic challenge.Direct asymmetric coupling of a tertiary carbon nucleophile with a tertiary carbon electrophile is themost straightforward approach,but it is sterically and energetically disfavored.Herein,we describe a catalytic asymmetric substitution,where racemic tertiary bromides coupled directly with racemic secondary or tertiary carbanion.
