为提高锂电池负极材料大倍率的充放电性能,以改进的Hummers法制备氧化石墨烯,并以葡萄糖为原料制备的碳纳米球和氧化石墨烯为原料,采用微波水热法制备碳纳米球/石墨烯复合物。当微波水热反应压强为2 MPa、碳纳米球与氧化石墨的质量比为1...为提高锂电池负极材料大倍率的充放电性能,以改进的Hummers法制备氧化石墨烯,并以葡萄糖为原料制备的碳纳米球和氧化石墨烯为原料,采用微波水热法制备碳纳米球/石墨烯复合物。当微波水热反应压强为2 MPa、碳纳米球与氧化石墨的质量比为10∶1、反应温度为180℃、反应时间为30 min时,制备3D多孔结构的碳球纳米/石墨烯复合材料。结果表明,碳球纳米/石墨烯作为锂离子电池的负极材料组装扣式锂离子电池,在1 000 m A/g大电流密度下,其首次放电比容量为1 026 m Ah/g,首次库仑效率为65.88%,循环50个周期后的充放电比容量稳定在539 m Ah/g,均高于碳球和石墨烯的比容量,展现了良好的大倍率充放电性能及倍率性能。展开更多
Lignin is the most abundant and important macromolecule in organic matter and its yield is second only to cellulose. Lignin is abundant in source, low in price, and has a large number of active groups such as methoxy ...Lignin is the most abundant and important macromolecule in organic matter and its yield is second only to cellulose. Lignin is abundant in source, low in price, and has a large number of active groups such as methoxy group and carboxyl group, so it has great utilization value. We used lignin as a carbon source to prepare porous carbon nanosphere(PCN) materials, and in-situ synthesized the MoS_ 2 on its surface. The high specific surface area(462.8 m^2/g), large pore volume and good electron conductivity of the porous carbon scaffold facilitated the reversible electro-chemical reaction of S towards metallic Li, and thus the nano-hybrid showed a high specific energy and excellent cycle stability which still remained 520m Ah/g after 50 cycles.展开更多
We demonstrate a simple and highly efficient strategy to synthesize MnO2/nitrogen-doped ultramicroporous carbon nanospheres（MnO2/N-UCNs） for supercapacitor application.MnO2/N-UCNs were fabricated via a template-free...We demonstrate a simple and highly efficient strategy to synthesize MnO2/nitrogen-doped ultramicroporous carbon nanospheres（MnO2/N-UCNs） for supercapacitor application.MnO2/N-UCNs were fabricated via a template-free polymerization of resorcinol/formaldehyde on the surface of phloroglucinol/terephthalaldehyde colloids in the presence of hexamethylenetetramine,followed by carbonization and then a redox reaction between carbons and KMnO4.As-prepared MnO2/N-UCNs exhibits regular ultramicropores,high surface area,nitrogen heteroatom,and high content of MnO2.A typical MnO2/N-UCNs with 57 wt.%MnO2 doping content（denoted as MnO2（57%）/N-UCNs） makes the most use of the synergistic effect between carbons and metal oxides.MnO2（57%）/N-UCNs as a supercapacitor electrode exhibits excellent electrochemical performance such as a high specific capacitance（401 F/g at 1.0 A/g） and excellent charge/discharge stability（86.3%of the initial capacitance after 10,000 cycles at 2.0 A/g） in 1.0 mol/L Na2SO4 electrolyte.The well-designed and high-performance MnO2/N-UCNs highlight the great potential for advanced supercapacitor applications.展开更多
文摘为提高锂电池负极材料大倍率的充放电性能,以改进的Hummers法制备氧化石墨烯,并以葡萄糖为原料制备的碳纳米球和氧化石墨烯为原料,采用微波水热法制备碳纳米球/石墨烯复合物。当微波水热反应压强为2 MPa、碳纳米球与氧化石墨的质量比为10∶1、反应温度为180℃、反应时间为30 min时,制备3D多孔结构的碳球纳米/石墨烯复合材料。结果表明,碳球纳米/石墨烯作为锂离子电池的负极材料组装扣式锂离子电池,在1 000 m A/g大电流密度下,其首次放电比容量为1 026 m Ah/g,首次库仑效率为65.88%,循环50个周期后的充放电比容量稳定在539 m Ah/g,均高于碳球和石墨烯的比容量,展现了良好的大倍率充放电性能及倍率性能。
基金Supported by the National Natural Science Foundation of China (21003099)Natural Science Foundation of Shannxi Province (2009JQ2010)+1 种基金Natural Science Research Project of the Education Department of Shannxi Province (09JK580)Peiyu Fund of Xi’an University of Science and Technology (200818)
基金the financial support of National Natural Science Foundation of China (No. 51803062)National Natural Science Foundation of Guangdong Province (No. 2018A030310379)+4 种基金National Postdoctoral Program for Innovation Talents (No. BX201700079)China Postdoctoral Science Foundation Funded Project (No. 2017M620371)and Foundation for Distinguished Young Talents in Higher Education of Guangdong Province (No. 2017KQNCX001)F. Chen thanks the financialsupport of Natural Science Foundation of China (No. 51673175)Natural Science Foundation of Zhejiang Province (Nos. LY16E030012, LY17E030006 and LY18E030009)
文摘Lignin is the most abundant and important macromolecule in organic matter and its yield is second only to cellulose. Lignin is abundant in source, low in price, and has a large number of active groups such as methoxy group and carboxyl group, so it has great utilization value. We used lignin as a carbon source to prepare porous carbon nanosphere(PCN) materials, and in-situ synthesized the MoS_ 2 on its surface. The high specific surface area(462.8 m^2/g), large pore volume and good electron conductivity of the porous carbon scaffold facilitated the reversible electro-chemical reaction of S towards metallic Li, and thus the nano-hybrid showed a high specific energy and excellent cycle stability which still remained 520m Ah/g after 50 cycles.
基金financially supported by the National Natural Science Foundation of China(Nos.21273162,21473122,21501135)the Science and Technology of Shanghai Municipality,China(No.14DZ2261100)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Large Equipment Test Foundation of Tongji University
文摘We demonstrate a simple and highly efficient strategy to synthesize MnO2/nitrogen-doped ultramicroporous carbon nanospheres（MnO2/N-UCNs） for supercapacitor application.MnO2/N-UCNs were fabricated via a template-free polymerization of resorcinol/formaldehyde on the surface of phloroglucinol/terephthalaldehyde colloids in the presence of hexamethylenetetramine,followed by carbonization and then a redox reaction between carbons and KMnO4.As-prepared MnO2/N-UCNs exhibits regular ultramicropores,high surface area,nitrogen heteroatom,and high content of MnO2.A typical MnO2/N-UCNs with 57 wt.%MnO2 doping content（denoted as MnO2（57%）/N-UCNs） makes the most use of the synergistic effect between carbons and metal oxides.MnO2（57%）/N-UCNs as a supercapacitor electrode exhibits excellent electrochemical performance such as a high specific capacitance（401 F/g at 1.0 A/g） and excellent charge/discharge stability（86.3%of the initial capacitance after 10,000 cycles at 2.0 A/g） in 1.0 mol/L Na2SO4 electrolyte.The well-designed and high-performance MnO2/N-UCNs highlight the great potential for advanced supercapacitor applications.
