Using Plasma to Replace Metals in Electrodes

Researchers in the United States were recently able to produce a new type of electrochemical cell, whose electrodes are made out of plasma, rather than conventional metals. The study was led by investigators at the Case Western Reserve University (CWRU).

According to the research team, this result may be of tremendous use for future attempts to redesign and improve batteries and fuel cells. At this point, these devices are manufactured and designed in an old-fashioned way that could benefit from some improvement.

In addition, the new study could have applications in the field of hydrogen fuel production and nanomaterial and polymer synthesis. Details of the new study appear in the latest issue of the esteemed Journal of the American Chemical Society (JACS).

The senior author of the paper was CWRU chemical engineering professor Mohan Sankaran. He worked together with former students Carolyn Richmonds and Brandon Bartling, students Megan Witzke and Seung Whan Lee and fellow chemical engineering professors Jesse Wainright and Chung-Chiun Liu.

“Plasmas formed at ambient conditions are normally sparks which are uncontrolled, unstable and destructive,” Sankaran explains. However, when controlled, plasma can be used for the most mundane applications, such as for instance brushing teeth.

“We’ve developed a plasma source that is stable at atmospheric pressure and room temperature which allows us to study and control the transfer of electrons across the interface of a plasma and an electrolyte solution,” the investigator explains.

Oddly enough, he adds, the team did not use an unconventional setup when putting their plasma electrode to the test. Their new electrochemical cell was made up of two glass jars, which were connected two each other via a glass tube.

The team also developed an electrolyte solution that contained potassium ferricyanide and potassium chloride, which they used to fill the jar. Afterwards, the researchers used a stainless steel tube to pump argon gas into the mix, so as to create a cathode.

In the small space separating the steel tube from the surface of the electrolyte, researchers noticed the formation of microplasma. When applying an electric current through this space, the electrons immediately reduced ferricyanide to ferrocyanide.