Graphene-like N,S-codoped bio-carbon nanosheets(GNSCS) were prepared by a facile and environment-friendly NaCl non-aqueous ionic liquid route to house sulfur for lithium-sulfur battery. The natural nori powder was cal...Graphene-like N,S-codoped bio-carbon nanosheets(GNSCS) were prepared by a facile and environment-friendly NaCl non-aqueous ionic liquid route to house sulfur for lithium-sulfur battery. The natural nori powder was calcined at 900°C for 3 h under Ar, in which NaCl non-aqueous ionic liquid can exfoliate carbon aggregates into nanosheets. The structural characterization of GNSCS by a series of techniques demonstrates the graphene-like feature.When evaluated as the matrix for sulfur cathode, GNSCS/S exhibits more prominent cycling stability and rate capability.A discharge capacity of 548 mA h g-1 at a current density of 1.6 A g-1 after 400 cycles was delivered with a capacity fade rate of only 0.13% per cycle and an initial Coulombic efficiency(CE) as high as 99.7%. When increasing the areal sulfur loading up to 3 mg cm-2, the discharge capacity can still be retained at 647 mA h g-1 after more than 100 cycles with a low capacity degradation of only ~0.30% per cycle. The features of N/S dual-doping and the graphene-like structure are propitious to the electron transportation, lithium-ion diffusion and more active sites for chemically adsorbing polysulfides. It is anticipated that other functional biochar carbon can also be attained via the low-cost, sustainable and green method.展开更多
The effect of different cold plasma treatments on the germination and seedling growth of alfalfa（Medicago sativa L.） seeds under simulated drought stress conditions was investigated.Polyethyleneglycol-6000（PEG 6000...The effect of different cold plasma treatments on the germination and seedling growth of alfalfa（Medicago sativa L.） seeds under simulated drought stress conditions was investigated.Polyethyleneglycol-6000（PEG 6000）with the mass fraction of 0%（purified water）, 5%, 10%,and 15% were applied to simulate the drought environment. The alfalfa seeds were treated with15 different power levels ranged between 0–280 W for 15 s. The germination potential,germination rate, germination index, seedling root length, seedling height, and vigor index were investigated. Results indicated significant differences between treated with proper power and untreated alfalfa seeds. With the increase of treatment power, these indexes mentioned above almost presented bimodal curves. Under the different mass fractions of PEG 6000, results showed that the lower power led to increased germination, and the seedlings presented good adaptability to different drought conditions. Meanwhile, higher power levels resulted in a decreased germination rate. Seeds treated with 40 W resulted in higher germination potential,germination rate, seedling height, root length, and vigor index. Vigor indexes of the treated seeds under different PEG 6000 stresses increased by 38.68%, 43.91%, 74.34%, and 39.20%respectively compared to CK_（0-0）, CK_（5-0）, CK_（10-0）, and CK_（15-0）（the control sample under 0%, 5%,10%, and 15% PEG 6000）. Therefore, 40 W was regarded as the best treatment in this research.Although the trend indexes of alfalfa seeds treated with the same power were statistically the same under different PEG 6000 stresses, the cold plasma treatment had a significant effect on the adaptability of alfalfa seeds in different drought environments. Thus, this kind of treatment is worth implementing to promote seed growth under drought situations.展开更多
基于Web of Science核心数据库对锂二次电池相关文献进行Cite Space可视化图谱分析。得到锂二次电池研究可分为3个阶段:起步阶段、平稳增长阶段和快速增长阶段。研究的主要力量主要集中在日本、美国、中国、法国和韩国,越来越多的国家...基于Web of Science核心数据库对锂二次电池相关文献进行Cite Space可视化图谱分析。得到锂二次电池研究可分为3个阶段:起步阶段、平稳增长阶段和快速增长阶段。研究的主要力量主要集中在日本、美国、中国、法国和韩国,越来越多的国家参与到研究中来,国家之间合作日益密切。以合成具有高能量密度高安全性能的电池材料为目的,探寻新型电极材料以及利用新型技术进行对锂二次电池进行结构和性能优化是研究的热点。最后总结指出目前研究较多的是层状锂的氧化物材料、尖晶石材料和聚阴离子材料,碳、硅等负极材料和固态电解质,对正极掺杂元素的选择与优化,结合纳米等新技术和高性能的新型材料是锂二次电池重要的发展方向。展开更多
基金the financial supports provided by the National Natural Science Foundation of China (21601108 and U1764258)Young Scholars Program of Shandong University (2017WLJH15)+1 种基金the Fundamental Research Funds of Shandong University (2016JC033 and 2016GN010)the Taishan Scholar Project of Shandong Province (ts201511004)
文摘Graphene-like N,S-codoped bio-carbon nanosheets(GNSCS) were prepared by a facile and environment-friendly NaCl non-aqueous ionic liquid route to house sulfur for lithium-sulfur battery. The natural nori powder was calcined at 900°C for 3 h under Ar, in which NaCl non-aqueous ionic liquid can exfoliate carbon aggregates into nanosheets. The structural characterization of GNSCS by a series of techniques demonstrates the graphene-like feature.When evaluated as the matrix for sulfur cathode, GNSCS/S exhibits more prominent cycling stability and rate capability.A discharge capacity of 548 mA h g-1 at a current density of 1.6 A g-1 after 400 cycles was delivered with a capacity fade rate of only 0.13% per cycle and an initial Coulombic efficiency(CE) as high as 99.7%. When increasing the areal sulfur loading up to 3 mg cm-2, the discharge capacity can still be retained at 647 mA h g-1 after more than 100 cycles with a low capacity degradation of only ~0.30% per cycle. The features of N/S dual-doping and the graphene-like structure are propitious to the electron transportation, lithium-ion diffusion and more active sites for chemically adsorbing polysulfides. It is anticipated that other functional biochar carbon can also be attained via the low-cost, sustainable and green method.
基金supported by China Agriculture Research System(CARS-34)
文摘The effect of different cold plasma treatments on the germination and seedling growth of alfalfa（Medicago sativa L.） seeds under simulated drought stress conditions was investigated.Polyethyleneglycol-6000（PEG 6000）with the mass fraction of 0%（purified water）, 5%, 10%,and 15% were applied to simulate the drought environment. The alfalfa seeds were treated with15 different power levels ranged between 0–280 W for 15 s. The germination potential,germination rate, germination index, seedling root length, seedling height, and vigor index were investigated. Results indicated significant differences between treated with proper power and untreated alfalfa seeds. With the increase of treatment power, these indexes mentioned above almost presented bimodal curves. Under the different mass fractions of PEG 6000, results showed that the lower power led to increased germination, and the seedlings presented good adaptability to different drought conditions. Meanwhile, higher power levels resulted in a decreased germination rate. Seeds treated with 40 W resulted in higher germination potential,germination rate, seedling height, root length, and vigor index. Vigor indexes of the treated seeds under different PEG 6000 stresses increased by 38.68%, 43.91%, 74.34%, and 39.20%respectively compared to CK_（0-0）, CK_（5-0）, CK_（10-0）, and CK_（15-0）（the control sample under 0%, 5%,10%, and 15% PEG 6000）. Therefore, 40 W was regarded as the best treatment in this research.Although the trend indexes of alfalfa seeds treated with the same power were statistically the same under different PEG 6000 stresses, the cold plasma treatment had a significant effect on the adaptability of alfalfa seeds in different drought environments. Thus, this kind of treatment is worth implementing to promote seed growth under drought situations.
文摘基于Web of Science核心数据库对锂二次电池相关文献进行Cite Space可视化图谱分析。得到锂二次电池研究可分为3个阶段:起步阶段、平稳增长阶段和快速增长阶段。研究的主要力量主要集中在日本、美国、中国、法国和韩国,越来越多的国家参与到研究中来,国家之间合作日益密切。以合成具有高能量密度高安全性能的电池材料为目的,探寻新型电极材料以及利用新型技术进行对锂二次电池进行结构和性能优化是研究的热点。最后总结指出目前研究较多的是层状锂的氧化物材料、尖晶石材料和聚阴离子材料,碳、硅等负极材料和固态电解质,对正极掺杂元素的选择与优化,结合纳米等新技术和高性能的新型材料是锂二次电池重要的发展方向。
