Surface engineered porous silicon for stable, high performance electrochemical supercapacitors

Abstract

Silicon materials remain unused for supercapacitors due to extreme reactivity of silicon with electrolytes. However, doped silicon materials boast a low mass density, excellent conductivity, a controllably etched nanoporous structure, and combined earth abundance and technological presence appealing to diverse energy storage frameworks. Here, we demonstrate a universal route to transform porous silicon (P-Si) into stable electrodes for electrochemical devices through growth of an ultra-thin, conformal graphene coating on the P-Si surface. This graphene coating simultaneously passivates surface charge traps and provides an ideal electrode-electrolyte electrochemical interface. This leads to 10–40X improvement in energy density, and a 2X wider electrochemical window compared to identically-structured unpassivated P-Si. This work demonstrates a technique generalizable to mesoporous and nanoporous materials that decouples the engineering of electrode structure and electrochemical surface stability to engineer performance in electrochemical environments. Specifically, we demonstrate P-Si as a promising new platform for grid-scale and integrated electrochemical energy storage.

Surface stiffening and enhanced photoluminescence of ion implanted cellulose – polyvinyl alcohol – silica composite

“…The electrical resistance of the polymer com-posites was determined from the high frequency intercept of the semicircle with the real part of the impedance. In the graph the semicircle represents the charge transfer resistance and the subsequent tail part denotes the proton diffusion within the sample (Oakes et al, 2013). Fig.…”

Hybrid Materials for Integrated Photonics

“…Concerning the fabrication of such material, controlled electrochemical techniques allow nowadays a fine supervision of the surface area, the porosity, and the pore morphology of the semiconductor [101]. In an article published recently, Oakes et al report the fabrication of stable electrodes for electrochemical devices using porous silicon coated with an ultrathin graphene layer [84]. They characterized their capacitors by performing charge-discharge measurements and electrochemical testing and observed energy densities of 2.5-3.5 Wh/Kg, which are similar to the ones of carbon-based supercapacitor currently available in the market.…”

“…Finally, in case of porous silicon, it is also possible to use and employ graphene as coating for the fabrication of electrochemical supercapacitor with high electrochemical stability [84].…”

Formation and structural studies of integrated membranes based on channel silicon

“…применения их в различных элементах, в частности сенсорах [1], накопителях энергии [2]. Одним из та-ких материалов является наноструктурированный кремний.…”