title: The synergistic effect achieved by combining different nitrogen-doped carbon shells for high performance capacitance.
abstract: Ellipsoid nitrogen-doped hollow carbon shells with different nitrogen contents and electrical conductivities were prepared using a simple calcination method by regulating the calcination temperature. Although a high nitrogen content promotes pseudocapacitance, it reduces the electrical conductivity of carbon, causing loss of capacitance. The best rate performance was achieved by a mixture of two types of ellipsoid nitrogen-doped hollow carbon shells, in which one contains a higher level of nitrogen with lower conductivity and higher pseudocapacitance, while the other contains a relatively lower level of nitrogen with higher conductivity. The enhanced performance can be explained by the synergistic effect of one component providing high pseudocapacitance and the other component serving as a highly electrically conductive network, which leads to activation of "nitrogen" to enhance pseudocapacitance performance. The mixed material showed a specific capacitance of 156.9 F g-1at a high current density of 10 A g-1, with no degradation after 10 000 cycles.
authors.affiliation: School of Advanced Materials, Peking University, Peking University Shenzhen Graduate School, Shenzhen 518055, China. panfeng@pkusz.edu.cn.
authors.forename: Jiangtao
authors.initials: J
authors.lastname: Hu
authors.affiliation: School of Advanced Materials, Peking University, Peking University Shenzhen Graduate School, Shenzhen 518055, China. panfeng@pkusz.edu.cn.
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.affiliation: School of Advanced Materials, Peking University, Peking University Shenzhen Graduate School, Shenzhen 518055, China. panfeng@pkusz.edu.cn.
authors.forename: Yandong
authors.initials: Y
authors.lastname: Duan
authors.affiliation: School of Advanced Materials, Peking University, Peking University Shenzhen Graduate School, Shenzhen 518055, China. panfeng@pkusz.edu.cn.
authors.forename: Chaokun
authors.initials: C
authors.lastname: Liu
authors.affiliation: School of Advanced Materials, Peking University, Peking University Shenzhen Graduate School, Shenzhen 518055, China. panfeng@pkusz.edu.cn.
authors.forename: Hanting
authors.initials: H
authors.lastname: Tang
authors.affiliation: School of Advanced Materials, Peking University, Peking University Shenzhen Graduate School, Shenzhen 518055, China. panfeng@pkusz.edu.cn.
authors.forename: Lingpiao
authors.initials: L
authors.lastname: Lin
authors.affiliation: School of Advanced Materials, Peking University, Peking University Shenzhen Graduate School, Shenzhen 518055, China. panfeng@pkusz.edu.cn.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lin
authors.affiliation: School of Advanced Materials, Peking University, Peking University Shenzhen Graduate School, Shenzhen 518055, China. panfeng@pkusz.edu.cn.
authors.forename: Haibiao
authors.initials: H
authors.lastname: Chen
authors.affiliation: School of Advanced Materials, Peking University, Peking University Shenzhen Graduate School, Shenzhen 518055, China. panfeng@pkusz.edu.cn.
authors.forename: Feng
authors.identifier: http://orcid.org/0000-0002-8216-1339
authors.initials: F
authors.lastname: Pan