Renewable energy plays an important role for “Decarbonization and Net-zero Carbon Emission”. However, the integration difficulty of renewable energy technologies in harsh climatic areas limits its applications in high latitude areas.

Especially, extreme weather events caused by global warming can bring unexpected snow, frost and ice on the surfaces of renewable energy devices, such as photovoltaic (PV) panels and wind turbine blades.

To tackle this problem, LI Longnan from Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences (CAS) and his co-workers from University of Illinois Urbana-Champaign developed a multifunctional coating material to remove snow, frost and ice from surfaces by using “Pulsed Joule Heating” method. This method involves pulsed interfacial Joule heating through thin conductive film, integrated with controlled surface wettability to achieve interfacial defrosting without bulk melting.

By melting only an ultra-thin layer of snow, ice and frost into water film, the remaining bulk accretion is removed under the synergetic effect of gravity (or shear forces like wind) and thin water layer. Compared to conventional Joule heating method, which would be too energy-intensive to melt bulk accretion completely, a single pulse of electrical current for heating the surface drastically reduces energy consumption and the time, which enables ultra-low energy density (E_in < 10 J cm^-2) and ultra-fast removal time (t ≈ 1 s) beyond what is currently available (E_in > 30 J cm^-2 and t > 1 min).

To control surface wettability and transmittance, a simple and ultra-scalable hydrothermal method was applied to thin aluminum layer on the module glass to achieve a nanoscale-thick aluminum oxyhydroxide nanostructures which is optically transparent. The combination of optical transparency and superhydrophobicity on the same coating allows for multi-functionality to enable “Pulsed Joule Heating”, self-cleaning and lossless power generation on PV panels.

"The technology might boost the widespreading of renewable energy technologies, heat pump heat exchangers and transport electrifications in harsh climate areas, particularly those affected by the heavy show, frost and ice aggregations," said LI.

Results of the work is published in Advanced Functional Materials.