Atomic Layer Deposition Alumina-Passivated Silicon Nanowires: Probing the Transition from Electrochemical Double-Layer Capacitor to Electrolytic Capacitor.
Silicon nanowires were coated by a 1-5 nm thin alumina layer by atomic layer deposition (ALD) in order to replace poorly reproducible and unstable native silicon oxide by a highly conformal passivating alumina layer. The surface coating enabled probing the behavior of symmetric devices using such electrodes in the EMI-TFSI electrolyte, allowing us to attain a large cell voltage up to 6 V in ionic liquid, together with very high cyclability with less than 4% capacitance fade after 106charge/discharge cycles. These results yielded fruitful insights into the transition between an electrochemical double-layer capacitor behavior and an electrolytic capacitor behavior. Ultimately, thin ALD dielectric coatings can be used to obtain hybrid devices exhibiting large cell voltage and excellent cycle life of dielectric capacitors, while retaining energy and power densities close to the ones displayed by supercapacitors.
University Grenoble Alpes , CEA, CNR INAC-SyMMES UMR 5819, F-38000 Grenoble, France.|University Grenoble Alpes , CEA, CNR INAC-SyMMES UMR 5819, F-38000 Grenoble, France.
Dorian
D
Gaboriau
University Grenoble Alpes , CEA, CNR INAC-SyMMES UMR 5819, F-38000 Grenoble, France.
Maxime
M
Boniface
University Grenoble Alpes , CEA, CNR INAC-SyMMES UMR 5819, F-38000 Grenoble, France.|University Grenoble Alpes , CEA, CNR INAC-SyMMES UMR 5819, F-38000 Grenoble, France.
Anthony
A
Valero
University Grenoble Alpes , CEA, CNR INAC-SyMMES UMR 5819, F-38000 Grenoble, France.
Dmitry
D
Aldakov
Institut des Matériaux Jean Rouxel, Université de Nantes - CNRS , 2 rue de la Houssinière, Nantes 44322 Cedex 3, France.|Réseau sur le Stockage Electrochimique de l'Energie (RS2E) , FR CNRS 3459, Amiens 80039 Cedex, France.
Thierry
T
Brousse
University Grenoble Alpes , CEA, CNR INAC-SyMMES UMR 5819, F-38000 Grenoble, France.
Pascal
P
Gentile
University Grenoble Alpes , CEA, CNR INAC-SyMMES UMR 5819, F-38000 Grenoble, France.
Said
http://orcid.org/0000-0002-4187-6039
S
Sadki
EMI-TFSI electrolyte; TEM; XPS; atomic layer deposition; chemical vapor deposition; silicon nanowires; supercapacitor