摘要
Three-dimensional(3D)carbon networks have been explored as promising capacitive materials thanks to their unique structural features such as large ion-accessible surface area and interconnected porous networks,thus enhancing both ions and electrons transport.Here,sustainable bacterial cellulose(BC)is used both precursor and template for facile synthesis of free-standing N,S-codoped 3Dcarbon networks(a-NSC)by the pyrolysis and activation of polyrhodanine coated BC.The synthesized a-NSC shows highly conductive interconnected porous networks(24S·cm^(-1)),large surface area(1 420m^2·g^(-1))with hierarchical meso-microporosity,and high-level heteroatoms codoping(N:3.1%in atom,S:3.2%in atom).Benefitting from these,a-NSC as binder-free electrode exhibits an ultrahigh specific capacitance of 340F·g^(-1)(24μF·cm^(-2))at the current density of 0.5A·g^(-1)in 6MKOH electrolyte,high-rate capability(71%at 20A·g^(-1))and excellent cycle stability.Furthermore,the assembled symmetrical supercapacitor displays a much short time constant of 0.35sin 1MTEABF4/AN electrolyte,obtaining a maximum energy density of 32.1W·h·kg^(-1 )at power density of 637W·kg^(-1).The in situ multi-heteroatoms doping enables biocellulose-derived carbon networks to exploit its full potentials in energy storage applications,which can be extended to other dimensional carbon nanostructures.
Three-dimensional （3D） carbon networks have been explored as promising capacitive materials thanks to their unique structural features such as large ion-accessible surface area and interconnected porous networks, thus enhancing both ions and electrons transport. Here, sustainable bacterial cellulose （BC） is used both precursor and template for facile synthesis of free-standing N, S-codoped 3D carbon networks （a-NSC） by the pyrolysis and activation of polyrhodanine coated BC. The synthesized a-NSC shows highly conductive interconnected porous networks （24 S·cm -1 ）, large surface area （1 420 m 2·g -1 ） with hierarchical meso-microporosity, and high-level heteroatoms codoping （N： 3.1 % in atom, S： 3.2 % in atom）. Benefitting from these, a-NSC as binder-free electrode exhibits an ultrahigh specific capacitance of 340 F·g -1 （24 μF·cm -2 ） at the current density of 0.5 A·g -1 in 6 M KOH electrolyte , high-rate capability （71% at 20 A·g -1 ） and excellent cycle stability. Furthermore, the assembled symmetrical supercapacitor displays a much short time constant of 0.35 s in 1 M TEABF 4/AN electrolyte, obtaining a maximum energy density of 32.1 W·h·kg -1 at power density of 637 W·kg -1 . The in situ multi-heteroatoms doping enables biocellulose-derived carbon networks to exploit its full potentials in energy storage applications, which can be extended to other dimensional carbon nanostructures.
基金
supported by the National Basic Research Program of China(973 Program)(No.2014CB239701)
the National Natural Science Foundation of China(Nos.51672128,51372116,21773118)
the Natural Science Foundation of Jiangsu Province(Nos.BK20150739,BK20151468)
the Prospective Joint Research Project of Cooperative Innovation Fund of Jiangsu Province(No.BY2015003-7)
the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
