An innovative 3-D nanoforest heterostructure made of polypyrrole coated silicon nanotrees for new high performance hybrid micro-supercapacitors

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2015-01, Vol.3 (26), p.13978-13985
• Main Authors: Aradilla, David, Gaboriau, Dorian, Bidan, Gérard, Gentile, Pascal, Boniface, Maxime, Dubal, Deepak, Gómez-Romero, Pedro, Wimberg, Jan, Schubert, Thomas J. S, Sadki, Saïd
• Format: Article
• Language: English
• Subjects: Capacitance; Chemical vapor deposition; Devices; Electrodes; Energy density; Nanostructure; Physics; Silicon; Three dimensional
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c5ta03435c

In this work, an innovative 3-D symmetric micro-supercapacitor based on polypyrrole (PPy) coated silicon nanotree (SiNTr) hybrid electrodes has been fabricated. First, SiNTrs were grown on silicon substrates by chemical vapor deposition (CVD) and then via an electrochemical method, the conducting polymer coating was deposited onto the surface of SiNTr electrodes. This study illustrates the excellent electrochemical performance of a hybrid micro-supercapacitor device using the synergistic combination of both PPy as the electroactive pseudo-capacitive material and branched SiNWs as the electric double layer capacitive material in the presence of an aprotic ionic liquid ( N -methyl- N -propylpyrrolidinium bis(trifluoromethylsulfonyl)imide; PYR 13 TFSI) as the electrolyte. The hybrid device exhibited a specific capacitance as high as ∼14 mF cm −2 and an energy density value of ∼15 mJ cm −2 at a wide cell voltage of 1.5 V using a high current density of 1 mA cm −2 . Furthermore, a remarkable cycling stability after thousands of galvanostatic charge-discharge cycles with a loss of approximately 30% was obtained. The results reported in this investigation demonstrated that PPy coated SiNTr-based micro-supercapacitors exhibit the best performances among hybrid micro-supercapacitors made of silicon nanowire electrodes grown by CVD in terms of specific capacitance and energy density. A micro-supercapacitor electrode made of polypyrrole coated silicon nanotrees.