Nanocarbon paper battery - supercapacitor

[hartiberlin]

Hmm,I am puzzled and mixed up now...
Does an acid have more H+ ions than its Minus ions ?

and
Does a Base have more OH- ions than Positive H+ ions ?

[ResinRat2]

Hmm,I am puzzled and mixed up now...
Does an acid have more H+ ions than its Minus ions ?

and
Does a Base have more OH- ions than Positive H+ ions ?

Yes to both. The acid disassociates almost completely as in the case of hydrochloric acid (strong acid):
HCl --> H⁺ + Cl^- this automatically gives an excess of H⁺ ions in the aqueous solution. The only other compound the hydrogen ion has to bond with in the aqueous solution is the water molecule in this way: H₂O + H⁺ <--> H₃O⁺.

The base dissociates as well as with sodium hydroxide (strong base). NaOH --> Na⁺ + OH^-

This automatically gives an excess of OH^- ions in the aqueous solution. Since water by itself has a small dissociation constant it also dissociates naturally (very small concentration in normal water)

H₂O <--> H⁺ + OH^-.

So the excess OH^- ions in the base solution would push the equilibrium to the water side.   This should give you what you are looking for.

I am just not sure if the Na⁺ concentration of ions in the basic solution and the Cl^-in the acid solution would somehow alter the potential for making a current. Maybe this would be the reason it wouldn't work? I am not sure.

[ResinRat2]

Sorry, I missed where it says that there is no water in this ionic liquid. Sorry Stephan. I'm on the wrong track.

[hansvonlieven]

G'day all,

Perhaps just a little off the subject, but have a look at this:

10/November/2005
Singapore Scientists Develop Personal Biochip Battery

(Singapore) -- Physicists in Singapore have succeeded in creating the first paper battery that generates electricity from urine. This new battery will be the perfect power source for cheap, disposable healthcare test-kits for diseases such as diabetes.

Scientists in research groups around the world are trying to design ever smaller ?biochips? that can test for a variety of diseases at once, give instant results, and, crucially, can be mass produced cheaply. However, until now, no one has been able to solve the problem of finding a power source as small and as cheap to fabricate as the detection technology itself.

Led by Dr. Ki Bang LEE, a research team at Singapore?s Institute of Bioengineering and Nanotechnology (IBN) have developed a paper battery that is small, cheap to fabricate, and which ingeniously uses the bio-fluid being tested (e.g. urine) as the power source for the testing device.

The chemical composition of urine is widely used as a way of testing for telltale signs of various diseases and as an indicator of a person?s general state of health. For example, the concentration of glucose in urine is a useful diagnostic tool for diabetics. The lead researcher, Dr. LEE, envisions a world where people will easily be able to monitor their health at home using disposable test-kits that do not need lithium batteries or external power sources.

Dr. LEE said, ?We are striving to develop cheap, disposable credit card-sized biochips for disease detection. Our battery can be easily integrated into such devices, supplying electricity upon contact with bio-fluids such as urine.?
Page 7 of 12 ATIP Japan Office Harks Bldg, 1F 6-15-21 Roppongi Minato-ku Tokyo 106-0032 Japan www.atip.org

The battery unit is made from a layer of paper that is steeped in copper chloride (CuCl) and sandwiched between strips of magnesium and copper. This ?sandwich? is laminated to keep it together. Lamination involves wrapping the ?sandwich? in transparent plastic film and passing it through a roller heated to 120?C. The final product has dimensions of 60 mm x 30 mm, and a thickness of just 1 mm (a little bit smaller than a credit card).

Writing in the Journal of Micromechanics and Microengineering, Dr. LEE describes how the battery was created and quantifies its performance. Using 0.2 mL of urine, they generated a voltage of around 1.5 V with a corresponding maximum power of 1.5 mW. Dr. Lee?s research team also found that the battery?s performance (such as voltage, power or duration) may be designed or adjusted by changing the geometry or materials used.

?Our urine-activated battery would be integrated into biochip systems for healthcare diagnostic applications,? says Dr. LEE. He envisions a world where people will easily be able to monitor their health at home, seeking medical attention only when necessary. ?These fully integrated biochip systems have a huge market potential,? adds Dr. LEE.
The work complements the "Intelligence Toilet" system, created by Japan's largest lavatory company, Toto, that can measure sugar levels in urine, blood pressure, body fat, and weight, but costs nearly US$3000.

(Source: Journal of Micromechanics and Microengineering)

Hans von Lieven

[hartiberlin]

Hi Hans,
it is not an urine battery, but just an urine ACTIVATED battery !

The consuming elements are still copper and mostly the magnesium metals !
The urine is just the electrolyte, but the most expensive consumed materials
are copper and magnesium in this design...

If anybody finds a battery solution, where only the urine is consumed,
please post it here.
Many thanks.

Regards, Stefan.