From coconut shell to porous graphene-like nanosheets for high-power supercapacitors
From coconut shell to porous graphene-like nanosheets for high-power supercapacitors
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从椰子壳到用于高功率超级电容器的多孔类石墨烯纳米片
DOI：
10.1039/c3ta10897j
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发表时间：
2013-01-01
影响因子：
11.9
通讯作者：
Fu, Honggang
中科院分区：
文献类型：
--
作者：
Sun, Li;Tian, Chungui;Fu, Honggang
具有多孔结构的片状石墨碳可以为能量存储提供低电阻路径和短离子扩散通道，因此有望成为大功率超级电容器的优良材料。本文首次以可再生生物质废椰子壳为原料，采用简单、经济的同时活化-石墨化方法合成了具有大表面积的多孔类石墨烯纳米片（PGNSs）。在合成过程中，通过金属前驱体与椰壳中的官能团配合，将石墨催化剂前驱体（FeCl3）和活化剂（ZnCl2）同时引入椰壳骨架中，从而在热处理条件下同时实现碳源的活化和石墨化。值得注意的是，椰子壳框架中的铁催化剂可以产生渗碳相，这在热解过程中对石墨烯样结构的形成起着关键作用。我们的研究结果表明，PGNSs具有高石墨度、极高的brunauer - emmet - teller表面积（SBET = 1874 m2 g−1）和大孔体积（1.21 cm3 g−1），具有良好的导电性。当用作超级电容器电极时，不使用任何导电添加剂，PGNSs表现出268 F g−1的高比电容，远高于仅活化制备的活性炭（210 F g−1）和仅石墨化的石墨碳（117 F g−1）。此外，PGNSs在KOH中经过5000次循环后，具有优异的循环耐久性和99.5%以上的库仑效率。值得注意的是，在有机电解质中，PGNSs在1ag−1时也显示出出色的196fg−1电容。在10 kW kg - 1的高功率密度下，能量密度可达54.7 W h kg - 1。本文开发的SAG策略将为低成本和大规模生产大功率超级电容器用PGNS电极材料提供一条新途径。
Sheet-like graphitic carbon with a porous structure can provide low-resistant pathways and short ion-diffusion channels for energy storage, and thus is expected to be an excellent material for high-power supercapacitors. Herein, porous graphene-like nanosheets (PGNSs) with a large surface area were synthesized for the first time via an easy and cost-effective SAG (simultaneous activation–graphitization) route from renewable biomass waste coconut shell. In the synthesis, the graphitic catalyst precursor (FeCl3) and activating agent (ZnCl2) were introduced simultaneously into the skeleton of the coconut shell through coordination of the metal precursor with the functional groups in the coconut shell, thus making simultaneous realization of activation and graphitization of the carbon source under heat treatment. Notably, the iron catalyst in the framework of the coconut shell can generate a carburized phase which plays a key role in the formation of a graphene-like structure during the pyrolytic process. Our results indicated that PGNSs possess good electrical conductivity due to the high graphitic degree, exceptionally high Brunauer–Emmett–Teller surface area (SBET = 1874 m2 g−1) and large pore volume (1.21 cm3 g−1). While being used as a supercapacitor electrode without the use of any conductive additives, PGNSs exhibit a high specific capacitance of 268 F g−1, much higher than that of activated carbon (210 F g−1) fabricated by only activation and graphitic carbon (117 F g−1) by only graphitization at 1 A g−1. Also, PGNSs show superior cycle durability and Coulombic efficiency over 99.5% after 5000 cycles in KOH. Remarkably, in an organic electrolyte, PGNSs also display an outstanding capacitance of 196 F g−1 at 1 A g−1. An energy density of up to 54.7 W h kg−1 could be achieved at a high power density of 10 kW kg−1. The SAG strategy developed here would provide a novel route for low-cost and large-scale production of PGNS electrode materials for high-power supercapacitors.