Element sulfur in nature is an insulating solid.While it has been tested that one-dimensional sulfur chain is metallic and conducting,the investigation on two-dimensional sulfur remains elusive.We report that molybden...Element sulfur in nature is an insulating solid.While it has been tested that one-dimensional sulfur chain is metallic and conducting,the investigation on two-dimensional sulfur remains elusive.We report that molybdenum disulfide layers are able to serve as the nanotemplate to facilitate the formation of two-dimensional sulfur.Density functional theory calculations suggest that confined inbetween layers of molybdenum disulfide,sulfur atoms are able to form two-dimensional triangular arrays that are highly metallic.As a result,these arrays contribute to the high conductivity and metallic phase of the hybrid structures of molybdenum disulfide layers and two-dimensional sulfur arrays.The experimentally measured conductivity of such hybrid structures reaches up to 223 S/m.Multiple experimental results,including X-ray photoelectron spectroscopy(XPS),transition electron microscope(TEM),selected area electron diffraction(SAED),agree with the computational insights.Due to the excellent conductivity,the current density is linearly proportional to the scan rate until 30,000 mV s^(−1) without the attendance of conductive additives.Using such hybrid structures as electrode,the two-electrode supercapacitor cells yield a power density of 10^(6) Wh kg^(−1) and energy density ~47.5 Wh kg^(−1) in ionic liquid electrolytes.Our findings offer new insights into using two-dimensional materials and their Van der Waals heterostructures as nanotemplates to pattern foreign atoms for unprecedented material properties.展开更多
基金the financial startup support and Tier 1 award from Northeastern University。
文摘Element sulfur in nature is an insulating solid.While it has been tested that one-dimensional sulfur chain is metallic and conducting,the investigation on two-dimensional sulfur remains elusive.We report that molybdenum disulfide layers are able to serve as the nanotemplate to facilitate the formation of two-dimensional sulfur.Density functional theory calculations suggest that confined inbetween layers of molybdenum disulfide,sulfur atoms are able to form two-dimensional triangular arrays that are highly metallic.As a result,these arrays contribute to the high conductivity and metallic phase of the hybrid structures of molybdenum disulfide layers and two-dimensional sulfur arrays.The experimentally measured conductivity of such hybrid structures reaches up to 223 S/m.Multiple experimental results,including X-ray photoelectron spectroscopy(XPS),transition electron microscope(TEM),selected area electron diffraction(SAED),agree with the computational insights.Due to the excellent conductivity,the current density is linearly proportional to the scan rate until 30,000 mV s^(−1) without the attendance of conductive additives.Using such hybrid structures as electrode,the two-electrode supercapacitor cells yield a power density of 10^(6) Wh kg^(−1) and energy density ~47.5 Wh kg^(−1) in ionic liquid electrolytes.Our findings offer new insights into using two-dimensional materials and their Van der Waals heterostructures as nanotemplates to pattern foreign atoms for unprecedented material properties.
