Search

Microsupercapacitors are attractiveenergy storage devices forintegration with autonomous microsensor networks due to their high-powercapabilities and robust cycle lifetimes. Here, we demonstrate poroussilicon nanowires synthesized via a lithography compatible low-temperaturewet etch and encapsulated in an ultrathin graphitic carbon sheath,as electrochemical double layer capacitor electrodes. Specific capacitancevalues reaching 325 mF cm–2are achieved, representingthe highest specific ECDL capacitance for planar microsupercapacitorelectrode materials to date. [ABSTRACT FROM AUTHOR]

Abstract: The effectiveness of silicon carbide (SiC) nanowires (NW) as electrode material for micro-supercapacitors has been investigated. SiC NWs are grown on a SiC thin film coated with a thin Ni catalyst layer via a chemical vapor deposition route at 950 °C. A specific capacitance in the range of ∼240 μF cm−2 is demonstrated, which is comparable to the values recently reported for planar micro-supercapacitor electrodes. Charge–discharge studies demonstrate the SiC nanowires exhibit exceptional stability, with 95% capacitance retention after 2 × 105 charge/discharge cycles in an environmentally benign, aqueous electrolyte. [Copyright &y& Elsevier]

The development of passivated silicon nanowire (SiNW) based micro-supercapacitor electrodes for on-chip applications using an environmentally benign aqueous electrolyte is reported. The SiNWs, produced by low-temperature (50 °C) electrochemical etching, corrode during charge/discharge cycling in the aqueous environment, but upon coating with a silicon carbide passivation layer, the corrosion is mitigated. The as-formed materials are in electrical contact with the substrate, requiring no additional current collector. The passivated NWs achieve capacitance values up to ∼1.7 mF/cm2 projected area (comparable to state-of-the art carbon based micro-supercapacitor electrodes), exhibit robust cycling stability, and maintain capacitive behavior over a wide range of charge/discharge rates. [ABSTRACT FROM AUTHOR]