摘要
有一个成长要求让混合 supercapacitor 系统克服存在产生的精力密度限制电的双层电容器(EDLC ) ,在力量与最小的牺牲导致下 generation-II supercapacitors 密度和周期生活。这里,一个先进基于 graphene 的混合系统,由插入 graphene 的 Li4Ti5O12 (LTO ) 组成合成阳极(G-LTO ) 和三维的多孔的 graphene 蔗糖阴极,为两个都联合 Li 离子电池(精力来源) 和 supercapacitors (力量来源) 的好处的目的被制作了。基于 Graphene 的材料关于混合 supercapacitor 的高效在两个电极起一个重要作用。例如,与 175
There is a growing demand for hybrid supercapacitor systems to overcome the energy density limitation of existing-generation electric double layer capacitors (EDLCs), leading to next generation-Ⅱ supercapacitors with minimum sacrifice in power density and cycle life. Here, an advanced graphene-based hybrid system, consisting of a graphene-inserted Li4Ti5O12 (LTO) composite anode (G-LTO) and a three-dimensional porous graphene-sucrose cathode, has been fabricated for the purpose of combining both the benefits of Li-ion batteries (energy source) and supercapacitors (power source). Graphene-based materials play a vital role in both electrodes in respect of the high performance of the hybrid supercapacitor. For example, compared with the theoretical capacity of 175 mA-h.g-1 for pure LTO, the G-LTO nanocomposite delivered excellent reversible capacities of 207, 190, and 176 mA·1h·g-1 at rates of 0.3, 0.5, and 1 C, respectively, in the potential range 1.0-2.5 V vs. Li/Li+; these are among the highest values for LTO-based nano- composites at the same rates and potential range. Based on this, an optimized hybrid supercapacitor was fabricated following the standard industry procedure; this displayed an ultrahigh energy density of 95 Wh·kg-1 at a rate of 0.4 C (2.5 h) over a wide voltage range (0-3 V), and still retained an energy density of 32 Wh·kg-1 at a high rate of up to 100 C, equivalent to a full discharge in 36 s, which is exceptionally fast for hybrid supercapacitors. The excellent performance of this Li-ion hybrid supercapacitor indicates that graphene-based materials may indeed play a significant role in next-generation supercapacitors with excellent electrochemical performance.
基金
The authors gratefully acknowledge financial support from Ministry of Science and Technology of the People's Republic of China (MOST) (Grants Nos. 2012CB933401 and 2011DFB50300), and National Natural Science Foundation of China (NSFC) (Grants Nos. 50933003 and 51273093).