Sustainable and recyclable thermoelectric nano paper that can convert heat losses into electricity
03/2019
New research raises hopes for thermoelectric materials that can convert ambient heat energy into electrical energy.
Researchers at the Barcelona Institute of Materials Science (ICMAB-CSIC) developed a new thermoelectric material concept published in the journal Energy & Environmental Science. This material is a device created by combining cellulose produced by bacteria with a small amount of conductive nanomaterial: carbon nanotubes , using sustainable and environmentally friendly techniques in the laboratory.
“Instead of making a material for energy, we process it,” explains Mariano Campoy-Quiles , researcher of the study. "Bacteria dispersed in an aqueous culture medium containing sugar and carbon nanotubes produce nanocellulose fibers that make up the device in which the carbon nanotubes are embedded," continues Campoy-Quiles .
"Thanks to cellulose fiber, we get a durable, flexible and degradable material, and thanks to carbon nanotubes, we get a material with high electrical conductivity," says Anna Laromaine , one of the researchers of this study. Another researcher of the study, Anna Roig , stated that "The aim is to approach the circular economy concept by using sustainable materials that are non-toxic for the environment, used in small quantities, recyclable and reusable " and said, "The device is made of sustainable and recyclable materials and has added value stated that it was high ".
Roig, "this material because of the synthetic polymer contained in the other thermoelectric material to comparison is with higher thermal stability allow for reaching 250 ° C. Furthermore, the device does not use toxic elements and cellulose, it glucose into an enzymatic by an operation easily degrade, back Because it can be recycled, carbon nanotubes, the most expensive element of the device, are recovered. Moreover, the thickness, color and transparency of the material can be controlled. said.
Campoy-Quiles explains that carbon nanotubes were chosen for their size: “Thanks to their nanoscale diameters and a few micron lengths, carbon nanotubes allow electric current, that is, electrical charges to pass through the material without interruption, even when used in very small quantities, even 1%. In addition, the use of such a small amount of nanotubes (up to 10%) makes the process very economical and energy efficient while maintaining 100% of the overall efficiency of the material. "
On the other hand, carbon nanotubes are similar in size to cellulose nanofibers, resulting in a homogeneous distribution on the material, Roig said. In addition, the use of these nanomaterials makes cellulose a more flexible and more resistant material. " said.
Campoy-Quiles explains: These devices can be used to generate electricity from waste / wasted heat with feed sensors, from the Internet of Things to agriculture. “In the near future, they can be used as wearable devices, for example in medical or sports activities. And, if efficiency is further optimized, these materials could turn into smart thermal insulators or hybrid photovoltaic-thermoelectric power generation systems . "
"Thanks to the high flexibility and scalability of cellulose, it can now be used in situations where the heat source has unusual forms or large areas, by completely covering the heat sources with these devices," Roig said. says.
Because bacterial cellulose is easily produced, this technology could be the first step towards a new energy approach where device users can build their own electric generators.