fig3

Figure 3. (A) Scheme towards more sustainable PIBs. (B) A schematic showing the paths for enhancing NMR signals from chemical environments in the SEI through DNP from different polarizing agents: in (i), organic biradicals are used as an exogenous source of polarization, and in (ii), paramagnetic metal ions are introduced as dopants into the bulk of the material. In both cases, microwave irradiation results in polarization transfer from the unpaired electrons to the nuclei in the sample, thereby enhancing their polarization and making them easily detectable in NMR.