Conducting-polymer-based supercapacitor devices and electrodes

All-polymer and paper-based energy storage devices have significant inherent advantages in comparison with many currently employed batteries and supercapacitors regarding environmental friendliness, flexibility, cost and versatility. The research within this field is currently undergoing an exciting development as new polymers, composites and paper-based devices are being developed. In this report, we review recent progress concerning the development of flexible energy storage devices based on electronically conducting polymers and cellulose containing composites with particular emphasis on paper-based batteries and supercapacitors. We discuss recent progress in the development of the most commonly used electronically conducting polymers used in flexible device prototypes, the advantages and disadvantages of this type of energy storage devices, as well as the two main approaches used in the manufacturing of paper-based charge storage devices.

Toward Flexible Polymer and Paper‐Based Energy Storage Devices

Composites of carbon nanotubes and conducting polymers can be prepared via chemical synthesis, electrochemical deposition on preformed carbon nanotube electrodes, or by electrochemical co-deposition. The composites combine the large pseudocapacitance of the conducting polymers with the fast charging/discharging double-layer capacitance and excellent mechanical properties of the carbon nanotubes. The electrochemically co-deposited composites are the most homogeneous and show an unusual interaction between the polymer and nanotubes, giving rise to a strengthened electron delocalisation and conjugation along the polymer chains. As a result they exhibit excellent electrochemical charge storage properties and fast charge/discharge switching, making them promising electrode materials for high power supercapacitors.

Carbon nanotube and conducting polymer composites for supercapacitors

A novel nanoarchitecture is developed by combining the nanostructured conductive polymer polypyrrole with highly electrically conductive graphene nanosheets in a multilayered configuration to achieve high specific capacitance and low electronic resistance for supercapacitor electrode applications. The fibrous network of polypyrrole nanowires with high electrolyte ionic accessibility was interspersed with electrically conductive monolayers of highly aligned large sized graphene nanosheets as a series of current collectors within the macroscopic configuration for enhanced electronic charge transport inside the electrode. A fabrication method relying on capillary force driven self-assembly coupled with the strong van der Waals attraction between highly aromatic graphene basal plane and π conjugated conductive polymer chains was employed to create a 100% binder free multilayered composite structure of these two distinct nanoscale elements to construct the electrode. This multilayer composite electrode exhibit...

Multilayered Nanoarchitecture of Graphene Nanosheets and Polypyrrole Nanowires for High Performance Supercapacitor Electrodes

Graphene quantum dots (GQDs) have attracted tremendous research interest due to the unique properties associated with both graphene and quantum dots. Here, a new application of GQDs as ideal electrode materials for supercapacitors is reported. To this end, a GQDs//GQDs symmetric microsupercapacitor is prepared using a simple electro-deposition approach, and its electrochemical properties in aqueous electrolyte and ionic liquid electrolyte are systematically investigated. The results show that the as-made GQDs micro-supercapacitor has superior rate capability up to 1000 V s − 1 , excellent power response with very short relaxation time constant ( τ 0 = 103.6 μ s in aqueous electrolyte and τ 0 = 53.8 μ s in ionic liquid electrolyte), and excellent cycle stability. Additionally, another GQDs//MnO 2 asymmetric supercapacitor is also built using MnO 2 nanoneedles as the positive electrode and GQDs as the negative electrode in aqueous electrolyte. Its specifi c capacitance and energy density are both two times higher than those of GQDs//GQDs symmetric micro-supercapacitor in the same electrolyte. The results presented here may pave the way for a new promising application of GQDs in micropower suppliers and microenergy storage devices.

Superior Micro‐Supercapacitors Based on Graphene Quantum Dots

Towards high power polypyrrole/carbon capacitors

We present a novel air-bridge subwavelength grating reflector with very high reflectivity be used as a top mirror in a VCSEL structure. We explain the design method, model the structure using both RCWA and FDTD, and predict the characteristics of a Fabry-Perot structure built with this reflector. We describe the fabrication of the suspended grating.

High reflectivity air-bridge subwavelength grating reflector and Fabry-Perot cavity in AlGaAs/GaAs

A shallow-etched, distributed grating is proposed as a wavelength demultiplexer. Modeling results predict up to 79% efficiency over a 60 nm wavelength range. Device fabrication and measurements are presented

Distributed-grating Wavelength Demultiplexer in SOI

We present a lithographically tunable, resonant subwavelength grating based Fabry-Perot cavity structure for mutliwavelength array devices. Theoretical and experimental performance of the cavity is discussed.

Resonant Grating Based Fabry-Perot Cavity in AlGaAs/GaAs

This paper presents simulation results on finite-sized sub-wavelength grating (SWG) optical structures. The structure is modeled with finite different time domain (FDTD). A Fabry-Perot structure built with this reflector is considered.

http://www.photonics.ece.mcgill.ca/Plant/dvp_pdf/CP-2006-05.pdf

D.T.H. Tan

Papers

Towards high power polypyrrole/carbon capacitors

High reflectivity air-bridge subwavelength grating reflector and Fabry-Perot cavity in AlGaAs/GaAs

Distributed-grating Wavelength Demultiplexer in SOI

Resonant Grating Based Fabry-Perot Cavity in AlGaAs/GaAs

Finite-Size Resonant Sub-Wavelength Grating High Reflectivity Mirror