Like graphene, perovskite is one of the star materials of the moment and could replace the silicon of solar panels. A team of North American researchers used this mineral to create new types of photovoltaic cells. According to them, an electric car equipped with such solar panels could recharge its lithium-ion batteries in total autonomy.
If electric cars don’t pollute their environment, the way their electricity is produced is debated. Indeed, if fossil fuels are used to make it, is the electric car really less polluting than the one equipped with a latest generation petrol engine? It is in these terms that a team of researchers from Case Western Reserve University (CWRU), in the United States, poses the problem to put forward its solution. It consists in using the very promising properties of a mineral, perovskite, to consider one day being able to recharge lithium-ion batteries electric vehicles from integrated solar panels.
In an article which has just appeared in the journal Nature Communications, Professor Liming Dai and his colleagues present a prototype charger for lithium-ion battery based on photovoltaic cells in perovskite. By mounting four of these cells in series, they were able to recharge a lithium-ion battery, obtaining a photoelectric and storage efficiency of 7.8%. According to them, this is the most efficient configuration for this type of charging solution combining solar with lithium-ion batteries. CWRU team sees potential for applications huge, starting with electric vehicles equipped with this type of miniature solar panels that could recharge their batteries independently.
Like graphene, perovskite is the star material of the moment, especially in the photovoltaic field. It is only since 2012 that the formidable properties of this family of minerals have been discovered with regard to solar energy. The rates of return of perovskite-based photovoltaic cells are already almost at the same level as those of silicon- based cells and there is still considerable room for improvement. Conversion of the spectrum of light larger solar, excellent mobility and separation electrical charges, low manufacturing cost make perovskite one of the most serious candidates for replacing silicon in solar panels. As an added bonus, the mineral can be used in liquid form to create photovoltaic cells in spray paint.
Perovskite: enormous potential but obstacles to be removed
As part of their laboratory test, Professor Dai’s team created three-layer photovoltaic cells converted into a single film of perovskite. Four of these cells connected in series achieved a conversion efficiency of 12.65%. Connected to lithium-ion batteries the size of a button cell, the photoelectric and storage efficiency rate reached 7.8% over ten charge-discharge cycles with a total duration of 18 hours. Researchers point out that their system was able to maintain almost identical charge-discharge curves during all cycles, demonstrating great stability and compatibility components. However, as promising as they may be, these perovskite-based photovoltaic cells have significant weaknesses which have not been resolved.
“The perovskites have brought considerable momentum to the photovoltaic community and are still full of promise but they also face very important obstacles such as their poor stability or their poor resistance to water … Furthermore, the records are achieved on demonstrators of a few square millimeters of surface,” underlines Daniel Lincot, director of the Institute for research and development on photovoltaic energy (Irdep) which is quoted in a recent article published on lejournal.cnrs.fr. And indeed, the four perovskite photovoltaic cells of the CWRU researchers measure only one square millimeter each …
The team at the North American university intends to continue development on small-scale prototypes in order to precisely improve the stability of cells in perovskite. And she seems rather confident. “In the very distant future, we envision that you could have this system at home to recharge your car and, in the long term, since perovskite photovoltaic cells can be manufactured in the form of flexible film, they could be integrated into the car itself.”