Hierarchical Microporous/Mesoporous Carbon Nanosheets for High-Performance Supercapacitors
Hierarchical Microporous/Mesoporous Carbon Nanosheets for High-Performance Supercapacitors
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DOI：
10.1021/am508794f
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发表时间：
2015-02-25
影响因子：
9.5
通讯作者：
Sevilla, Marta
中科院分区：
文献类型：
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作者：
Fuertes, Antonio B.;Sevilla, Marta
提出了一种简单的一锅法合成具有优异性能的超级电容器电极的高孔纳米碳片。该方法基于有机盐(即葡萄糖酸钠)在700-900℃的温度范围内的碳化。碳纳米片具有大的长径比(长度/厚度接近10(2)-10(3))，厚度在40-200 nm的范围内，高比表面积(SBET)高达1390m(2)g(-1)，以及在微孔-中孔范围内具有分级组织的孔洞。重要的是，通过额外的活化步骤，质地特性可以得到显著增强(最高可达1890m(2)g(-1))。纳米片状结构(短扩散路径)和分级微孔/介孔结构都允许离子在碳质基质中快速传输，从而获得优异的电化学性能。因此，在1M硫酸溶液中，层次化纳米片在150Ag(-1)的超高放电电流下表现出高达140Fg(-1)的比容，在1MTEABF4/An中，在120Ag(-1)的超高放电电流下表现出100Fg(-1)的比容。在水溶液中记录的最大比功率类似于20-30kW kg(-1)，在有机电解液中类似于90-110kW kg(-1)。这些有希望的功率特性伴随着出色的循环稳定性。
A straightforward one-pot approach for the synthesis of highly porous carbon nanosheets with an excellent performance as supercapacitor electrodes is presented. The procedure is based on the carbonization of an organic salt (i.e., sodium gluconate) at a temperature in the range of 700-900 degrees C. The carbon nanosheets have a large aspect ratio (length/thickness approximate to 10(2)-10(3)), a thickness within the range of 40-200 nm, high BET surface areas (SBET) of up to 1390 m(2) g(-1), and a porosity with a hierarchical organization in the micropore-mesopore range. Importantly, via an additional activation step, the textural properties can be substantially enhanced (SBET up to 1890 m(2) g(-1)). Both the nanosheet morphology (short diffusional paths) and the hierarchical microporous/mesoporous pore structure allow the rapid transport of ions throughout the carbonaceous matrix, leading to excellent electrochemical performance. Thus, the hierarchical nanosheets exhibit specific capacitances of up to 140 F g(-1) at an ultrahigh discharge current of 150 A g(-1) in 1 M H2SO4 and 100 F g(-1) at 120 A g(-1) in 1 M TEABF4/AN. The maximum specific power recorded in an aqueous electrolyte is similar to 20-30 kW kg(-1) and similar to 90-110 kW kg(-1) in an organic electrolyte. These promising power characteristics are accompanied by excellent cycling stability.