Researchers are Developing Nanocomposites to Battle Solar Cell Corrosion

A team of researchers at Sandia National Laboratories, led by Erik Spoerke along with Texas A&M professor Jaime Grunlan, is developing nanocomposite films made from inexpensive materials as barriers against water vapor and corrosive gases. The research at Sandia concluded that there is a connection between corrosion and arc faults in electric connections, and nanocomposites could dramatically improve solar cell reliability. The team believes these composite materials, which are 100 times thinner than a strand of human hair, will improve ways to protect solar cells from corrosion. As Sandia explains, many people think of corrosion as only in terms of the rust on cars or oxidation that blackens silver. However, it also can damage electronics and connections in solar panels, lowering the amount of electricity produced. A 2002 study by the National Association of Corrosion Engineers, backed by the Federal Highway Administration, estimated corroding metals in various industries, infrastructure and manufacturing cost $276 billion annually. Sandia has studied corrosion for decades, analyzing the problem in all kinds of systems because anything containing metal is susceptible to it. Solar cells’ electrical components are protected from corrosion by encapsulating polymers, sealants and glass, but water vapor and corrosive gases can permeate as materials and packaging degrade. Engineers use corrosion chambers to study different materials in systems that must meet particular corrosion requirements, or to expose an electronic component to the environment to see what happens over time. “Instead of waiting for 30 years of operation outside under the sun, we bring our PV [photovoltaic]  panels inside to expose them to much higher concentrations of light or put them in thermal chambers to simulate the equivalent of years of temperature cycles,” said Sandia’s Olga Lavrova. Accelerated lifetime experiments show in six months what could happen over decades, she added. The bigger challenge, Sandia notes, is studying the mechanisms underlying corrosion. The chemistry of the atmosphere, the particles landing on surfaces, relative humidity and temperature all play a role, but the difficult part is understanding how these factors are connected and interact with materials.