Supercapacitors -- Design and construction, Graphene -- Electric properties, Electrodes -- Technological innovations, Supercapacitors -- Electric properties
M. F. El-Kady and R. B. Kaner, “Scalable fabrication of high-power graphene micro-supercapacitors for flexible and on-chip energy storage,” Nature Communications, vol. 4, p. 1475, Feb. 2013.
Supercapacitors are electrical components that have higher energy density than regular capacitors. Currently, they are large and bulky which makes it hard to be implemented into smaller electronic devices or on-chip. In Scalable Fabrication of High-power Graphene Micro-supercapacitors for Flexible and On-chip Energy Storage, El-Kady and Kaner developed an inexpensive and reliable method for scaling down supercapacitors to be approximately 7.53 x 5.35 mm. To make the laser-scribed graphene (LSG) micro-supercapacitors, an aqueous solution of graphite oxide (GO) is deposited onto a polyethylene terephthalate film that is adhered to a LightScribe disc and allowed to dry. The disc is then inserted into a LightScribe DVD drive and run at the highest contrast setting. The GO turns to LSG in an interdigitated pattern. The GO that is unetched between the LSG electrodes acts as a separator. A hydrogel-polymer electrolyte is drop casted on the pattern creating a planar micro-supercapacitor. The GO and electrolyte form a catalyst that promotes the movement of ions between the electrodes. Copper tape is attached to each electrode and the MSC is sealed around the edges with Kapton tape.
Fabrication process of a single interdigitated laser-scribed micro-supercapacitor
The characterization of the micro-supercapacitor is to be investigated in future research. Methods of characterization include field emission scanning electron microscopy and optical microscopy to view the molecular surface structure of the MSC and its electronic properties. I-V curves were measured using a two-electrode setup. This provides a way to calculate the conductivity and thickness of the film. Other properties of interest are the LSG-MSC’s energy and power density, its capacitance at various frequencies, and various current densities. These were attained using galvanostatic curves and using the following equations:
P = (ΔE)2/4RESRV W/cm3
E = CV×(ΔE)2/(2×3600) Wh/cm3
Cdev = i/(-dV/dt) F
Owens, Kimi D., "Laser-Scribed Graphene Micro-Supercapacitors" (2018). Undergraduate Research & Mentoring Program. 24.