Electrokinetic Water Battery

Aug 18, 2002
Electricity discovery draws overwhelming response


Edmonton researchers discover new way of generating electricity

EDMONTON (CP) - News that two Alberta professors have discovered a new way to produce electricity has generated an immediate and overwhelming response from the international community.

Daniel Kwok, an engineering professor at the University of Alberta, said Monday he has been inundated with e-mails and media calls from around the globe. "I've been getting phone calls from all over the world, like London, Australia, Asia-Pacific, the U.S.," Kwok said. "I was surprised. I was not expecting it to be like that."

Fellow inventor Larry Kostiuk, chairman of the mechanical engineering department, was in Los Angeles on Monday, doing interviews with U.S. networks, Kwok said.

The discovery was announced in a research paper by Kwok and Kostiuk. The paper appeared Monday in the Journal of Micromechanics and Microengineering, published by the London-based Institute of Physics.

With the help of two graduate students, the two professors were able to light a small bulb by simply squeezing a syringe of ordinary tap water through a glass "filter" with microscopic-sized holes they call microchannels.

They invented their "electrokinetic" water battery by harnessing the natural energy that is created on a very tiny scale when a flowing liquid meets a solid surface, creating an electrical charge. Water forced through a microchannel results in the movement of positive and negatives ions in such a way that one end becomes positive and the other negative.

The inventors are particularly excited by the fact the electricity is produced cleanly and involves no moving parts.

The discovery could in a matter of years lead to batteries for everyday items such as cellphones and calculators being powered by pressurized water.

Because theoretically there is nothing to prevent the technology from being scaled up, it could eventually lead to larger power production, although that would require huge bodies of water to work on a commercial scale, Kostiuk said.

Kwok said not only has he received correspondence from academics already offering suggestions for the research, it appears to have captured the public imagination as well - judging from the many congratulatory e-mails from individuals.

"Everybody knows about electricity and everybody knows about water. . . It really caught public attention because . . . nobody has been able to come up with a new method of generating electricity for the last 160 years."

There may be medical applications as well, he said.

But the professors know they are just on the cusp of a new field of knowledge.

Much work needs to be done to understand the new power source and how it can be developed. "I see it as pioneering work," Kwok said.

Hydroelectricity is created by converting the kinetic energy of falling water to electrical energy through a turbine and a generator.

Kostiuk and Kwok's discovery uses the potential energy of the microscopic interaction between the liquid and the solid to directly produce electricity.

Although the power generated from a single cell is extremely small, millions of parallel channels can be used to increase the output.

In electromagnetic induction (discovered by Michael Faraday in 1831), electricity is produced by the interaction of an electric conductor with a magnetic field. The process is used in electric generators.

The university moved quickly to apply for a patent and has been working with the scientists to develop commercial strategies.

Major electricity breakthroughs:

1800: Allesandro Volta discovers electrochemical effect, used in batteries.

1821: Thomas Seebeck discovers Seebeck effect, used in thermoelectric generators.

1831: Michael Faraday discovers electromagnetic induction, used in electric generators.

1839: Edmond Becquerel discovers photovoltaic effect, used in solar cells.

1839: Sir William Grove discovers proton exchange membranes used in fuel cells.

2002: Larry Kostiuk and Daniel Kwok discover electrokinetic effect, could lead to pressurized water battery and other uses.
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I knew the job was dangerous when I took it ...
Staff member
Jul 19, 2004
Out of Bounds
This October 2003 article in Nature:


... describes how this approach is inefficient enough to make one question what applications could reasonably exploit it.
Electrokinetic microchannel battery by means of electrokinetic and microfluidic phenomena
Water pushed through narrow pores powers a new kind of battery.

A new battery harvests electricity from flowing water. One of its creators, Larry Kostiuk, claims that it could make water "an alternative energy source to rival wind and solar power". But its lack of efficiency may stand in the way.

Kostiuk's team at the University of Alberta in Canada have powered a light bulb by pumping water through a glass filter riddled with tiny holes1. The 'electrokinetic battery' might drive portable electronic devices such as mobile phones, the group suggests.

How does it work? Inside the device, some water molecules fall apart into positively charged hydrogen ions and negatively charged hydroxide ions. In the prototype, the surface of the porous glass filter is negatively charged - this attracts hydrogen ions to form a layer.

The pores are about ten thousandths of a millimetre wide - the same size as this layer. So the ions accumulate preferentially in the pores. Pressure is then applied to drive the liquid through the pores and move the charged ions from one side of the porous membrane to the other. In other words, a current flows.

The current is tiny, but it adds up when the water flows through thousands of pores at once. Gravity drives water through, as the inlet pipe is 30 centimetres above the outlet. It produces a current of around one microamp - enough to power microscopic gears and switches.

To catch on, an electrokinetic battery would have to compete with conventional batteries and fuel cells, which are becoming ever smaller and more powerful.

Currently the technology is very inefficient. Kostiuk and his colleagues estimate that it converts a fraction of a percent of the mechanical energy of water flow into electrical energy. In contrast, hydroelectric turbines can achieve around 80% efficiency.

“Water will be the coal of the future”
This is a serious problem for any plan to use the technique for large-scale power generation. Even if the water from a mountain stream or dam could be channelled through some vast, porous filter, would anyone want to harness its energy with the new technology unless it performed much better than existing methods?

But the approach might help to extract low levels of power from natural environments that are not usually deemed potential energy sources, the researchers point out. For example, porous rock could provide the necessary narrow channels. Groundwater flowing through could create small currents for buried electrodes to harvest. This is akin to how thermoelectric devices reap low-level geothermal heat.

The notion of energy from water has an enduring appeal. Jules Verne mooted it in The Mysterious Island (1874): "Water will be the coal of the future." And water-powered vehicles are proposed regularly. But no one has yet got around the fact that water itself is not a fuel.

Yang, J. , Lu, F. , Kostiuk, L. W. & Kwok, D. Y. Electrokinetic microchannel battery by means of electrokinetic and microfluidic phenomena. Journal of Micromechanics and Microengineering, 13, 963 - 970, doi:10.1088/0960-1317/13/6/320 (2003).