ABSTRACT
Zwitterions are a unique class of molecules that possess two functional groups bearing electric charges, one positive and the second negative. This setup results in peculiar properties such as high water retention and anti-fouling capability. Therefore, zwitterionic coatings and gels are commonly applied in, e.g., biosensing and bioelectronic devices.
Despite those applications, there are other perspectives for zwitterionic materials. Recently, they have gained attention in the fields of energy storage and conversion. In particular, gel electrolytes for batteries and solid-state supercapacitors based on zwitterionic polymers have significantly higher ionic conductivity compared to standard electrolytes based on, e.g., poly(vinyl alcohol). Moreover, the capacitance of devices with zwitterionic electrolytes is generally a few times higher and retained after a larger number of cycles. Zwitterions are also prominent interlayers between photoactive materials and electrical contacts in organic and perovskite solar cells facilitating charge injection.
Considering the unique properties of zwitterions and a large variety of available structures, they have become an important point of scientific attention in the field of energy storage and conversion. Although some concepts have already been developed, there is plenty to be discovered about these materials. In our opinion, zwitterions can be regarded as the most prospective ones in energy fields.
