Abstract
Building of hierarchical core-shell hetero-structures is currently the subject of intensive research in the electrochemical field owing to its potential for making improved electrodes for high-performance micro-supercapacitors. Here we report a novel architecture design of hierarchical MnO2@silicon nanowires (MnO2@SiNWs) hetero-structures directly supported onto silicon wafer coupled with Li-ion doped 1-Methyl-1-propylpyrrolidinium bis(trifluromethylsulfonyl)imide (PMPyrrBTA) ionic liquids as electrolyte for micro-supercapacitors. A unique 3D mesoporous MnO2@SiNWs in Li-ion doped IL electrolyte can be cycled reversibly across a voltage of 2.2 V and exhibits a high areal capacitance of 13 mFcm−2. The high conductivity of the SiNWs arrays combined with the large surface area of ultrathin MnO2 nanoflakes are responsible for the remarkable performance of these MnO2@SiNWs hetero-structures which exhibit high energy density and excellent cycling stability. This combination of hybrid electrode and hybrid electrolyte opens up a novel avenue to design electrode materials for high-performance micro-supercapacitors.
Highlights
Plain silicon nanowires (SiNWs)[10], as well as doped SiNWs11,12, silicon carbide nanowires[13], porous silicon coated with gold[14,15]
MnO2 films with common ionic liquid (IL) electrolyte-based supercapacitors have been investigated with an electrochemical quartz-crystal microbalance (EQCM), X-ray photoemission spectroscopy (XPS)[19] and in situ X-ray absorption spectroscopy (XAS)[20]
Hierarchical ultrathin MnO2 nanoflakes can be controllably grown on SiNWs in order to fabricate MnO2@SiNWs core-shell hybrid electrodes by a simple solution method followed by a thermal annealing treatment
Summary
Plain silicon nanowires (SiNWs)[10], as well as doped SiNWs11,12, silicon carbide nanowires[13], porous silicon coated with gold[14,15]. An emerging attractive concept is to directly grow smart integrated array architectures with the combination of two types of materials and/or nanostructures on conducting substrates as binder-free electrodes for micro-supercapacitors In this way, many advantages such as multiple accessible electroactive sites, short ion transport pathways, superior electron collection efficiency, and even fascinating synergetic properties are simultaneously achieved to deliver high ASC, sustained cycle life and rate performance. Based on the above considerations, we have fabricated and patented [ref] a unique design of hierarchical MnO2@SiNWs core-shell hetero-structure coupled with a novel Li-ion doped ionic liquid as electrolyte, which is based on LiClO4 and 1-Methyl-1-propylpyrrolidinium bis(trifluromethylsulfonyl)imide (PMPyrrBTA) for high-performance micro-supercapacitors. In this case the slim SiNWs are the “core” and ultrathin MnO2 nanoflakes the “shell” layer. This MnO2@SiNWs device can be cycled reversibly at a high operating voltage of 2.2 V with good capacitance, energy density and excellent cycling stability in a LiClO4-PMPyrrBTA IL electrolyte
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
