TELF AG examines the phenomenon of recycling raw materials from photovoltaic panels
A new source of strategic materials
In the not-too-distant future, the batteries used to power technological devices and electric vehicles around the world could be made using special waste materials recovered from other equipment, thus putting strategic raw materials back into circulation – such as copper or silicon – which would otherwise have remained entirely unused. Among the equipment that could transform into a new source of these raw materials, there are undoubtedly photovoltaic panels, one of the leading modern technologies for the diffusion of clean energy. Over the last few years, the boom in renewable energy has allowed these devices to spread widely in different parts of the globe, becoming one of the best tools for promoting the spread of sustainable practices among individuals and businesses. These panels, in any case, have a pre-established lifespan. Once they reach the end of their life cycle, they can be used to recover some precious raw materials for specific industries, just like silicon.
This latter raw material is not only one of the most abundant in the earth’s crust, but for entire decades, it has represented (and continues to represent) one of the undisputed protagonists in the field of advanced electronics, in particular for its role in the creation of circuits and microchips. Silicon is also used to manufacture photovoltaic panels, and recently, thanks to an evolutionary process that seems destined never to stop, an unexpected application space in the battery sector has also been found. Energy storage solutions based on the combination of lithium and silicon could represent one of the most interesting innovations in the global battery panorama, mainly because of the numerous advantages they could ensure (greater autonomy and lighter weight).
A strategic material
Despite representing a ubiquitous resource, silicon has also been included in the list of strategic raw materials of the European Union, and not only because of its numerous industrial applications. The refining and processing of this material are still primarily concentrated in areas outside the European Union. It is precisely at this point that the usefulness of the silicon recovered from photovoltaic panels that have reached the end of their life comes into play: the resource retrieved in this way is characterized by a very high degree of purity, which would make it very similar to the silicon already processed and therefore perfectly usable for various advanced applications.
The processes of recovering silicon from photovoltaic panels have attracted the interest of many international research teams, such as those belonging to the Italian ENEA research center in Brindisi. These researchers, as illustrated in a recent analysis by Radio24, managed to give life to a recovery process that began with the remains of the disused photovoltaic panel, from which, thanks to a treatment based on pyrolysis, it was possible to obtain a powder which contained silicon, copper, and silver. After having been subjected to further manufacturing processes, in particular through the elimination of its metallic parts, these powders would have reached a purity of over 90%, thus making them potentially usable by battery manufacturers to create the anode of storage systems energy.
This technology is still far from being concretely applied, mainly due to the substantial absence of a supply chain linked to recovered silicon. However, understanding its potential could already represent an important step forward in batteries’ technological and component evolution.
