title: Nitrogen-Doped Hollow Carbon Nanospheres for High-Performance Li-Ion Batteries.
abstract: N-doped carbon materials is of particular attraction for anodes of lithium-ion batteries (LIBs) because of their high surface areas, superior electrical conductivity, and excellent mechanical strength, which can store energy by adsorption/desorption of Li+at the interfaces between the electrolyte and electrode. By directly carbonization of zeolitic imidazolate framework-8 nanospheres synthesized by an emulsion-based interfacial reaction, we obtained N-doped hollow carbon nanospheres with tunable shell thickness (20 nm to solid sphere) and different N dopant concentrations (3.9 to 21.7 at %). The optimized anode material possessed a shell thickness of 20 nm and contained 16.6 at % N dopants that were predominately pyridinic and pyrrolic. The anode delivered a specific capacity of 2053 mA h g-1at 100 mA g-1and 879 mA h g-1at 5 A g-1for 1000 cycles, implying a superior cycling stability. The improved electrochemical performance can be ascribed to (1) the Li+adsorption dominated energy storage mechanism prevents the volume change of the electrode materials, (2) the hollow nanostructure assembled by the nanometer-sized primary particles prevents the agglomeration of the nanoparticles and favors for Li+diffusion, (3) the optimized N dopant concentration and configuration facilitate the adsorption of Li+; and (4) the graphitic carbon nanostructure ensures a good electrical conductivity.
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, and ‡CAS Key Laboratory of Materials for Energy Conversion, iChEM, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China.
authors.forename: Yufen
authors.initials: Y
authors.lastname: Yang
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, and ‡CAS Key Laboratory of Materials for Energy Conversion, iChEM, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China.
authors.forename: Song
authors.initials: S
authors.lastname: Jin
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, and ‡CAS Key Laboratory of Materials for Energy Conversion, iChEM, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, and ‡CAS Key Laboratory of Materials for Energy Conversion, iChEM, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China.
authors.forename: Zhenzhen
authors.initials: Z
authors.lastname: Du
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, and ‡CAS Key Laboratory of Materials for Energy Conversion, iChEM, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China.
authors.forename: Huarong
authors.initials: H
authors.lastname: Liu
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, and ‡CAS Key Laboratory of Materials for Energy Conversion, iChEM, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China.
authors.forename: Jia
authors.initials: J
authors.lastname: Yang
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, and ‡CAS Key Laboratory of Materials for Energy Conversion, iChEM, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China.
authors.forename: Hangxun
authors.identifier: http://orcid.org/0000-0003-1645-9003
authors.initials: H
authors.lastname: Xu
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, and ‡CAS Key Laboratory of Materials for Energy Conversion, iChEM, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China.
authors.forename: Hengxing
authors.identifier: http://orcid.org/0000-0003-2851-9878
authors.initials: H
authors.lastname: Ji
keywords: carbon nanospheres; hollow structures; lithium-ion batteries; nitrogen-doping; porous materials