Ordinary Pen Ink Is Useful For Building A Supercapacitor

A research group in China has discovered that the ink in an ordinary pen makes for a good coating when building a supercapacitor. The team, from Peking University (Beijing National Laboratory for Molecular Sciences) describe in their paper published in Advanced Materials, how they used pen ink to coat carbon fibers as part of a process in creating a supercapacitor that was not only bendable but able to cover a large surface area.

Supercapacitors are energy storage devices that are able to be charged and more importantly, discharged much more quickly than conventional capacitors. They serve as a sort of bridge between conventional capacitors and batteries and are used in applications where a quick change in load is required, such as in balancing electrical grids. The focus of most ongoing research involving supercapacitors centers around trying to bring down costs. Most conventional systems use carbon to carbon electrodes or in some cases metal oxide electrodes, both of which tend to cost a lot. More recent research has focused on graphene or carbon nanotubes because of their unique electrical properties. This new research involved looking at ordinary pen ink after the researchers noted that many types of it just happen to contain carbon nanoparticles.

The researchers built the new supercapacitor by applying the pen ink to dual carbon fibers which were then encased, along with a spacer wire, in plastic and filled with a liquid conducting solution, i.e. an electrolyte. The result was a very thin (millimeter) diameter supercapacitor in the shape of a double wire cable, that could be bent to form a full circle and that could also cover a large area; one gram of ink produced enough of the supercapacitor cable to cover twenty seven square meters of material; all this with little to no loss in performance. They also point out that their supercapacitor is able to hold up to ten times more charge than comparable conventional supercapacitors and outperforms them as well.

Because of the unique properties of the supercapacitor they’ve made, the researchers believe it could be applied to cloth material which would result in wearable electronics such as sensors or even as components in future phones or other handheld devices.

The Role Of Unique Properties Of Graphene

New research by Columbia Engineering demonstrates remarkable optical nonlinear behavior of graphene that may lead to broad applications in optical interconnects and low-power photonic integrated circuits. With the placement of a sheet of graphene just one-carbon-atom-thick, the researchers transformed the originally passive device into an active one that generated microwave photonic signals and performed parametric wavelength conversion at telecommunication wavelengths.

They have engineered a graphene-silicon device whose optical nonlinearity enables the system parameters (such as transmittance and wavelength conversion) to change with the input power level. Using different optical frequencies to tune the radio frequency, they found that the graphene-silicon hybrid chip achieved radio frequency generation with a resonant quality factor more than 50 times lower than what other scientists have achieved in silicon. The researchers also were able to observe that, by optically driving the electronic and thermal response in the silicon chip, they could generate a radio frequency carrier on top of the transmitted laser beam and control its modulation with the laser intensity and color.

Until recently, researchers could only isolate graphene as single crystals with micron-scale dimensions, essentially limiting the material to studies confined within laboratories. “The ability to synthesize large-area films of graphene has the obvious implication of enabling commercial production of these proven graphene-based technologies,” explains James Hone, associate professor of mechanical engineering, whose team provided the high quality graphene for this study. “But large-area films of graphene (is an allotrope of carbon) can also enable the development of novel devices and fundamental scientific studies requiring graphene samples with large dimensions. This work is an exciting example of both-large-area films of graphene enable the fabrication of novel opto-electronic devices, which in turn allow for the study of scientific phenomena.”

And now, the recent excellent work done by this group of Columbia researchers demonstrates that graphene is also unique electro-optical material for ultrafast nonlinear optical modulation when it is combined with silicon photonic crystal structures. This opens an important doorway for many novel optoelectronic device applications, such as 

Activated Charcoal: Medical Uses and Side Effects

Currently, the uses of activated charcoal(CAS: 7440-44-0, also called activated carbon) differ according to whether they are approved by physicians or alternative medicine practitioners. Studies of the effectiveness of treatments with activated charcoal have been conducted, and dosages have been standardized for some maladies. The most widely accepted uses of activated carbon are as treatments for poisoning and overdoses.

Common Medical Uses
Activated charcoal is not an antidote for all medication overdoses, but it is effective for quinine, carbamazepine, and phenobarbitals, among other medications listed in medical records. Used as an antidote, the activated carbon absorbs organic chemicals in the stomach before the chemicals can spread through the body. Effectiveness as an antidote, however, is dependent upon the amount of poison ingested and how quickly medical attention is received. Some physicians treat adults with oral doses of its laxatives to purge poisons from the body quickly; patients receiving this treatment should be carefully monitored for diarrhea.

Alternative medicine practitioners have other uses for activated charcoal; some use it as a general detoxifying agent when treating recreational amphetamine and cocaine use, or even as a hangover remedy for alcohol use. Other uses include combating blood pathogens such as viruses, harmful bacteria, and systemic infections. Additionally, for those with buildups of toxins in their systems due to exposure to chemicals and toxic substances at work, practitioners use activated carbon along with special diets and saunas to treat compromised immune systems.

Side Effects
Most activated charcoal side effects are fairly benign, but the possibility of more severe effects is one of the reasons it should only be used under a doctor’s supervision.

The most common side effects is a tendency to turn the patient’s stools black. Normally, black stool is a cause for concern, but in this case, it usually only represents the charcoal clearing from the body. Diarrhea can often occur following this treatment, but unless it continues for a prolonged amount of time afterward, it is not a dangerous effect. Vomiting is another common side effect, but does not usually indicate a severe reaction.

Somewhat less common activated carbon side effects are also related to the gastrointestinal tract. These can include constipation, as well as a swelling or pain in the stomach. Constipation is often due to the charcoal absorbing water from the GI tract, and usually doesn’t require further medical attention.

Other side effects involve more severe forms of the mechanisms underlying constipation. Charcoal can absorb water, and occasionally this can lead to dehydration. Persistent constipation can result in a blockage of the GI tract, which can also be dangerous if left untreated. Allergic reactions may sometimes occur as one of the activated charcoal side effects.