Developing a high sulfur(S)-loading cathode with high capacity utilization and long term cyclability is a key challenge for commercial implementation of Li-S battery technology.To overcome this challenge,we propose a ...Developing a high sulfur(S)-loading cathode with high capacity utilization and long term cyclability is a key challenge for commercial implementation of Li-S battery technology.To overcome this challenge,we propose a solid-phase conversion sulfur cathode by using an edible fungus slag-derived porous carbon(CFS)as sulfur host to fabricate the S/CFS composite and meanwhile,utilizing the vinyl carbonate(VC)as co-solvent of the ether-based electrolyte to in-situ form a protective layer on the S/CFS composite surface through its nucleophilic reaction with the freshly generated lithium polysulfides(LiPSs)at the very beginning of initial discharge,thus isolating the interior sulfur from the outer electrolyte and inhibiting the further generation of soluble LiPSs.Benefitting from the ultrahigh specific surface area of>3,000 m^(2)·g^(−1),ideal pore size of<4 nm,and large pore volume of>2.0 cm^(3)·g^(−1)of the CFS host matrix,the S/CFS cathode even with a high S-loading of 80 wt.%(based on the weight of S/CFS composite)can still operate in a solid-phase conversion manner in the VC-ether co-solvent electrolyte to exhibit a high reversible capacity of 1,557 mAh·g^(−1),a high rate capability with 50%remaining capacity at 2 A·g^(−1)and a high cycling efficiency of 99.9%over 500 cycles.The results presented in this work suggest that a combined action of solid-phase conversion electrochemistry and nanoarchitectured host structure may provide a new path for the design and development of practical lithium-sulfur batteries.展开更多
Ecological restoration measures implemented in China have profoundly impacted vegetation NPP.This study aimed to estimate the effects of the land conversion and management measures on the grassland ecosystem in semi-a...Ecological restoration measures implemented in China have profoundly impacted vegetation NPP.This study aimed to estimate the effects of the land conversion and management measures on the grassland ecosystem in semi-arid regions.Land use data were employed from 2000 to 2015 to compare land conversion and coverage changes in Xilingol grassland.Then,the contributions of land conversion and management policies were quantified by assessing the difference between actual NPP and climate-induced NPP changes.The results indicated that the grassland area had a net loss of 534.42 km^(2),and the net area of increased vegetation coverage was 74,683.05 km^(2).Furthermore,the total NPP increased by 8,010.73 Gg C·yr^(−1)(1 Gg=10^(9)g),of which the human activities,including grazing management measures(+6,809.40 Gg C·yr^(−1))and land conversion(45.72 Gg C·yr^(−1))contributed to 85.58%of the increase in NPP.Transformation from desert and farmland dominated grassland expansion and NPP increase,while urbanization and desertification caused large grassland reduction and NPP loss.The grazing management increased vegetation NPP in most regions except for some regions in the desert steppe and the farming-pastoral zone.Related policies should be further adjusted to strengthen the management of the desert steppe and farming-pastoral regions.展开更多
Two-dimensional(2 D) transition metal phosphides(TMPs) are predicted with many novel properties and various applications. As a member of TMPs family, molybdenum phosphide(MoP) exhibits many exotic physicochemical prop...Two-dimensional(2 D) transition metal phosphides(TMPs) are predicted with many novel properties and various applications. As a member of TMPs family, molybdenum phosphide(MoP) exhibits many exotic physicochemical properties. However, the synthesis of high-quality2 D MoP single crystals is not reported due to the lack of reliable fabrication method, which limits the exploration of 2 D MoP. Here, we report the growth of high-quality ultrathin MoP single crystals with thickness down to 10 nm on liquid metals via chemical vapor deposition(CVD). The smooth surface of liquid Ga is regarded as a suitable growth substrate for producing 2 D MoP single crystals. The Mo source diffuses toward the Ga surface due to the high surface energy to react with phosphorus source, thus to fabricate ultrathin MoP single crystals. Then, we study the second harmonic generation(SHG) of 2 D MoP for the first time due to its intrinsic noncentrosymmetric structure. Our study provides an new approach to synthesize and explore other 2 D TMPs for future applications.展开更多
基金supported by the National Key R&D Program of China(No.2021YFB3800300)the China Postdoctoral Science Foundation(No.2022T150494).
文摘Developing a high sulfur(S)-loading cathode with high capacity utilization and long term cyclability is a key challenge for commercial implementation of Li-S battery technology.To overcome this challenge,we propose a solid-phase conversion sulfur cathode by using an edible fungus slag-derived porous carbon(CFS)as sulfur host to fabricate the S/CFS composite and meanwhile,utilizing the vinyl carbonate(VC)as co-solvent of the ether-based electrolyte to in-situ form a protective layer on the S/CFS composite surface through its nucleophilic reaction with the freshly generated lithium polysulfides(LiPSs)at the very beginning of initial discharge,thus isolating the interior sulfur from the outer electrolyte and inhibiting the further generation of soluble LiPSs.Benefitting from the ultrahigh specific surface area of>3,000 m^(2)·g^(−1),ideal pore size of<4 nm,and large pore volume of>2.0 cm^(3)·g^(−1)of the CFS host matrix,the S/CFS cathode even with a high S-loading of 80 wt.%(based on the weight of S/CFS composite)can still operate in a solid-phase conversion manner in the VC-ether co-solvent electrolyte to exhibit a high reversible capacity of 1,557 mAh·g^(−1),a high rate capability with 50%remaining capacity at 2 A·g^(−1)and a high cycling efficiency of 99.9%over 500 cycles.The results presented in this work suggest that a combined action of solid-phase conversion electrochemistry and nanoarchitectured host structure may provide a new path for the design and development of practical lithium-sulfur batteries.
基金This work was supported primarily by the State Key Research Development Program of China(No.2016YFC0501101),(No.2016YFC0503603).
文摘Ecological restoration measures implemented in China have profoundly impacted vegetation NPP.This study aimed to estimate the effects of the land conversion and management measures on the grassland ecosystem in semi-arid regions.Land use data were employed from 2000 to 2015 to compare land conversion and coverage changes in Xilingol grassland.Then,the contributions of land conversion and management policies were quantified by assessing the difference between actual NPP and climate-induced NPP changes.The results indicated that the grassland area had a net loss of 534.42 km^(2),and the net area of increased vegetation coverage was 74,683.05 km^(2).Furthermore,the total NPP increased by 8,010.73 Gg C·yr^(−1)(1 Gg=10^(9)g),of which the human activities,including grazing management measures(+6,809.40 Gg C·yr^(−1))and land conversion(45.72 Gg C·yr^(−1))contributed to 85.58%of the increase in NPP.Transformation from desert and farmland dominated grassland expansion and NPP increase,while urbanization and desertification caused large grassland reduction and NPP loss.The grazing management increased vegetation NPP in most regions except for some regions in the desert steppe and the farming-pastoral zone.Related policies should be further adjusted to strengthen the management of the desert steppe and farming-pastoral regions.
基金supported by the National Natural Science Foundation of China (21673161 and 21905210)the Sino-German Center for Research Promotion (GZ 1400)。
文摘Two-dimensional(2 D) transition metal phosphides(TMPs) are predicted with many novel properties and various applications. As a member of TMPs family, molybdenum phosphide(MoP) exhibits many exotic physicochemical properties. However, the synthesis of high-quality2 D MoP single crystals is not reported due to the lack of reliable fabrication method, which limits the exploration of 2 D MoP. Here, we report the growth of high-quality ultrathin MoP single crystals with thickness down to 10 nm on liquid metals via chemical vapor deposition(CVD). The smooth surface of liquid Ga is regarded as a suitable growth substrate for producing 2 D MoP single crystals. The Mo source diffuses toward the Ga surface due to the high surface energy to react with phosphorus source, thus to fabricate ultrathin MoP single crystals. Then, we study the second harmonic generation(SHG) of 2 D MoP for the first time due to its intrinsic noncentrosymmetric structure. Our study provides an new approach to synthesize and explore other 2 D TMPs for future applications.
