Creating adsorption sites by doping heteroatoms into the graphitic structures of carbon electrodes is an effective strategy for improving lithium storage in lithium-ion batteries.In this work,we prepared carbon nanotu...Creating adsorption sites by doping heteroatoms into the graphitic structures of carbon electrodes is an effective strategy for improving lithium storage in lithium-ion batteries.In this work,we prepared carbon nanotubes with controllable morphology and controllable nitrogen-doping level by a one-step pyrolysis method through adjusting the amount of urea used during synthesis.Under the synergistic effects of high temperature and Ni-catalyst migration,the carbon nanosheets generated by pyrolysis become coiled into tube-like structures.Characterization using Raman and x-ray photoelectron spectroscopy revealed that the B and N atoms were successfully co-doped into the resultant carbon nanotubes.When the obtained materials were used as lithium-ion battery anodes,reversible specific capacities of 337.11 and 187.62 mA h g^(−1) were achieved at current densities of 100 and 2000 mA g^(−1),respectively.Moreover,a capacity of 140.53 mA h g^(−1) was retained after 2000 cycles at a current density of 2000 mA g^(−1).The mechanism of lithium storage in these carbon materials was elucidated using cyclic voltammetry tests.Regarding other functional applications,the synthesized composite carbon nanotube material could also be used in other energy-storage battery systems,such as in the sulfur-carrying structures of lithium-sulfur batteries and in the three-dimensional porous structures of sodium batteries.展开更多
文摘Creating adsorption sites by doping heteroatoms into the graphitic structures of carbon electrodes is an effective strategy for improving lithium storage in lithium-ion batteries.In this work,we prepared carbon nanotubes with controllable morphology and controllable nitrogen-doping level by a one-step pyrolysis method through adjusting the amount of urea used during synthesis.Under the synergistic effects of high temperature and Ni-catalyst migration,the carbon nanosheets generated by pyrolysis become coiled into tube-like structures.Characterization using Raman and x-ray photoelectron spectroscopy revealed that the B and N atoms were successfully co-doped into the resultant carbon nanotubes.When the obtained materials were used as lithium-ion battery anodes,reversible specific capacities of 337.11 and 187.62 mA h g^(−1) were achieved at current densities of 100 and 2000 mA g^(−1),respectively.Moreover,a capacity of 140.53 mA h g^(−1) was retained after 2000 cycles at a current density of 2000 mA g^(−1).The mechanism of lithium storage in these carbon materials was elucidated using cyclic voltammetry tests.Regarding other functional applications,the synthesized composite carbon nanotube material could also be used in other energy-storage battery systems,such as in the sulfur-carrying structures of lithium-sulfur batteries and in the three-dimensional porous structures of sodium batteries.
