This data set collects,compares and contrasts the capacities and structures of a series of hard carbon materials,and then searches for correlations between structure and electrochemical performance.The capacity data o...This data set collects,compares and contrasts the capacities and structures of a series of hard carbon materials,and then searches for correlations between structure and electrochemical performance.The capacity data of the hard carbons were obtained by charge/discharge tests and the materials were characterized by XRD,gas adsorption,true density tests and SAXS.In particular,the fitting of SAXS gave a series of structural parameters which showed good characterization.The related test details are given with the structural data of the hard carbons and the electrochemical performance of the sodium-ion batteries.展开更多
近年来,人们对利用低温炭化工艺制备煤基无定形炭材料作为锂离子电池(LIBs)和钠离子电池(SIBs)的负极材料产生了兴趣。然而,煤衍生炭材料的炭化机制仍然不太清楚。因此,本文选取烟煤为原料,探究了煤炭到无定形炭材料的化学、微晶和孔隙...近年来,人们对利用低温炭化工艺制备煤基无定形炭材料作为锂离子电池(LIBs)和钠离子电池(SIBs)的负极材料产生了兴趣。然而,煤衍生炭材料的炭化机制仍然不太清楚。因此,本文选取烟煤为原料,探究了煤炭到无定形炭材料的化学、微晶和孔隙结构演变过程。随着温度的升高(低于1000℃),材料结构发生局部变化,碳层的迁移和小分子物质的释放导致了层间距(3.69-3.82A)和缺陷密度(1.26-1.90)逐渐增大,并且产生了丰富的纳米微孔结构。当温度升至1000~1600℃时,层间距和缺陷密度开始逐渐减小。在LIBs中,经1000℃炭化制备的样品表现出最佳的电化学性能。在0.1 C倍率测试下可逆容量达到384 mAh g^(-1),在5 C倍率下仍能保持170 mAh g^(-1),表现出优异的倍率性能。在SIBs中,经1200℃炭化制备的样品在0.1 C倍率测试下具有270.1 mAh g^(-1)的可逆容量和高达86.8%的首次库伦效率。本研究为煤基炭材料的精细化制备提供了理论支撑。展开更多
Nitrogen doping has been widely used to improve the performance of carbon electrodes in supercapacitors,particularly in terms of their high-frequency response.However,the charge storage and electrolyte ion response me...Nitrogen doping has been widely used to improve the performance of carbon electrodes in supercapacitors,particularly in terms of their high-frequency response.However,the charge storage and electrolyte ion response mechanisms of different nitrogen dopants at high frequencies are still unclear.In this study,melamine foam carbons with different configurations of surfacedoped N were formed by gradient carbonization,and the effects of the configurations on the high-frequency response behavior of the supercapacitors were analyzed.Using a combination of experiments and first-principle calculations,we found that pyrrolic N,characterized by a higher adsorption energy,increases the charge storage capacity of the electrode at high frequencies.On the other hand,graphitic N,with a lower adsorption energy,increases the speed of ion response.We propose the use of adsorption energy as a practical descriptor for electrode/electrolyte design in high-frequency applications,offering a more universal approach for improving the performance of N-doped carbon materials in supercapacitors.展开更多
基金supported by the National Natural Science Foundation of China(22379157)CAS Project for Young Scientists in Basic Research(YSBR-102)+2 种基金Institute of Coal Chemistry,Chinese Academy of Sciences(SCJC-XCL-2023-13,SCJCXCL-2023-10)Talent Projects for Outstanding Doctoral Students to Work in Shanxi Province(E3SWR4791Z)Fundamental Research Program of Shanxi Province(202403021222485).
文摘This data set collects,compares and contrasts the capacities and structures of a series of hard carbon materials,and then searches for correlations between structure and electrochemical performance.The capacity data of the hard carbons were obtained by charge/discharge tests and the materials were characterized by XRD,gas adsorption,true density tests and SAXS.In particular,the fitting of SAXS gave a series of structural parameters which showed good characterization.The related test details are given with the structural data of the hard carbons and the electrochemical performance of the sodium-ion batteries.
文摘近年来,人们对利用低温炭化工艺制备煤基无定形炭材料作为锂离子电池(LIBs)和钠离子电池(SIBs)的负极材料产生了兴趣。然而,煤衍生炭材料的炭化机制仍然不太清楚。因此,本文选取烟煤为原料,探究了煤炭到无定形炭材料的化学、微晶和孔隙结构演变过程。随着温度的升高(低于1000℃),材料结构发生局部变化,碳层的迁移和小分子物质的释放导致了层间距(3.69-3.82A)和缺陷密度(1.26-1.90)逐渐增大,并且产生了丰富的纳米微孔结构。当温度升至1000~1600℃时,层间距和缺陷密度开始逐渐减小。在LIBs中,经1000℃炭化制备的样品表现出最佳的电化学性能。在0.1 C倍率测试下可逆容量达到384 mAh g^(-1),在5 C倍率下仍能保持170 mAh g^(-1),表现出优异的倍率性能。在SIBs中,经1200℃炭化制备的样品在0.1 C倍率测试下具有270.1 mAh g^(-1)的可逆容量和高达86.8%的首次库伦效率。本研究为煤基炭材料的精细化制备提供了理论支撑。
文摘Nitrogen doping has been widely used to improve the performance of carbon electrodes in supercapacitors,particularly in terms of their high-frequency response.However,the charge storage and electrolyte ion response mechanisms of different nitrogen dopants at high frequencies are still unclear.In this study,melamine foam carbons with different configurations of surfacedoped N were formed by gradient carbonization,and the effects of the configurations on the high-frequency response behavior of the supercapacitors were analyzed.Using a combination of experiments and first-principle calculations,we found that pyrrolic N,characterized by a higher adsorption energy,increases the charge storage capacity of the electrode at high frequencies.On the other hand,graphitic N,with a lower adsorption energy,increases the speed of ion response.We propose the use of adsorption energy as a practical descriptor for electrode/electrolyte design in high-frequency applications,offering a more universal approach for improving the performance of N-doped carbon materials in supercapacitors.
