Separadores poliméricos para celdas electroquímicas

Secondary electrochemical batteries are currently amongst the most active technology and research areas, since they are at the base of decarbonization, mobility and even digitalization. Besides the search for higher capacity cells, it is crucial to make them longer-lasting and safer, that is, to avoid shortcircuiting, toxic or corrosive liquid leaks or flammability. The first separators were conceived as mere mechanical barriers allowing free ion flow. However, separators can offer much more, and modify fundamental electrolyte properties, such as transport number, polarization or unwanted ion shuttling, avoiding parasitic reactions, contributing to more homogeneous metallic deposition, and lower capacity loss on cycling. Likewise, separators can reduce cell flammability, pose a barrier to dendrites or act as thermal shutdown of the cell. In this article, the structure and properties of separators currently used in batteries, and the new functionalities for future separators are described.