Facile low-temperature synthesis of hematite quantum dots anchored on a three-dimensional ultra-porous graphene-like framework as advanced anode materials for asymmetric supercapacitors. Issue 29 (19th May 2016)

• Record Type: Journal Article
• Authors: Li, Yunyong; Zhang, Haiyan; Wang, Shanxing; Lin, Yingxin; Chen, Yiming; Shi, Zhicong; Li, Na; Wang, Wenguang; Guo, Zaiping
• Is Part Of: Journal of materials chemistry. Volume 4:Issue 29(2016)
• Page Start: 11247
• Page End: 11255
• Publication Date: 2016-05-19
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c6ta02927b
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Hematite quantum dots anchored on a 3D ultraporous graphene-like framework as anode materials showed superior electrochemical performance for asymmetric supercapacitors. Abstract : A composite consisting of well-dispersed and ultrafine hematite quantum-dots (∼2.7 nm) anchored on a three-dimensional ultra-porous graphene-like framework (denoted as Fe2 O3 -QDs–3D GF) has been designed by a facile and scalable strategy. In the composite, the ultra-porous 3D GF with high conductivity and high surface area was used as a conductive matrix with surface defective sites for the controllable growth of uniformly dispersed, ultra-small Fe2 O3 -QDs. The graphene framework can tightly hold a great amount of Fe2 O3 -QDs, thereby ensuring high utilization of active materials and the required conductivity to individual Fe2 O3 -QDs. The ultra-small-sized Fe2 O3 -QDs anchored on the 3D GF can endow the composite with a superior high surface area and enough active sites for electrochemical reactions, thus giving the composite a large specific capacitance. As expected, the as-prepared Fe2 O3 -QDs–3D GF electrode exhibited a high specific capacitance of 945 F g −1 at 1.0 A g −1 in a three-electrode system in 2.0 mol L −1 KOH aqueous solution. In addition, high-performance asymmetric supercapacitors have been fabricated with Fe2 O3 -QDs–3D GF as the anode and 3D hierarchical porous graphene (HPG) as the cathode, and they showed a very high energy density of 77.7 W h kg −1 at a power density of 0.40 kW kg −1 and maximum power density of 492.3 kW kg −1, as well as excellent cycling stability.