Electrochemical and Corrosion Stability of Nanostructured Silicon by Graphene Coatings: Toward High Power Porous Silicon Supercapacitors

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• 作者：Shahana Chatterjee ; Rachel Carter ; Landon Oakes ; William R. Erwin ; Rizia Bardhan ; Cary L. Pint
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：May 22, 2014
• 年：2014
• 卷：118
• 期：20
• 页码：10893-10902
• 全文大小：552K
• 年卷期：v.118,no.20(May 22, 2014)
• ISSN：1932-7455

文摘

We demonstrate the electrochemical stability of nanostructured silicon in corrosive aqueous, organic, and ionic liquid media enabled by conformal few-layered graphene heterogeneous interfaces. We demonstrate direct gas-phase few-layered graphene passivation (d = 0.35 nm) at temperatures that preserve the structural integrity of the nanostructured silicon. This passivation technique is transferrable both to silicon nanoparticles (Si-NPs) as well as to electrochemically etched porous silicon (P-Si) materials. For Si-NPs, we find the graphene-passivated silicon to withstand physical corrosion in NaOH aqueous conditions where unpassivated Si-NPs spontaneously dissolve. For P-Si, we demonstrate electrochemical stability with widely different electrolytes, including NaOH, enabling these materials for electrochemical supercapacitors. This leads us to develop high-power on-chip porous silicon supercapacitors capable of up to 10 Wh/kg and 65 kW/kg energy and power densities, respectively, and 5 Wh/kg energy density at 35 kW/kg鈥攃omparable to many of the best high-power carbon-based supercapacitors. As surface reactivity wholly dictates the utilization of nanoscale silicon in diverse applications across electronics, energy storage, biological systems, energy conversion, and sensing, we emphasize direct formation of few-layered graphene on nanostructured silicon as a means to form heterogeneous on-chip interfaces that can maintain stability in even the most reactive of environments.