An acid-assisted vacuum filtration approach towards flexible PDI/SWCNT cathodes for highly stable organic lithium ion batteries

An acid-assisted vacuum filtration approach is developed in this work to fabricate perylene diimide (PDI) and single wall carbon nanotube (SWCNT) based organic lithium ion battery (LIB) cathodes by using concentrated sulfuric acid (H2SO4) as the solvent. PDI and SWCNT can be readily dispersed in H2SO4 by the protonation of their aromatic frameworks, thus rendering the effective combination of them in the acidic solution. The resulting PDI/SWCNT films are highly appealing flexible cathodes for LIBs by associating the intriguing electrochemical activity of PDI with the excellent electric conductivity and mechanical stability of SWCNT. Either with lithium foils or pre-lithiated carbon clothes as the anodes, the LIBs with PDI/SWCNT cathodes can deliver highly stable electrochemical performances in terms of rate capability and cycling stability. The PDI/SWCNT cathodes also have very good mechanical stability, enabling the LIBs based on them to reserve the battery performances at different bending states. The excellent electrochemical stability of the PDI/SWCNT cathodes is attributable to the acidic solution based processing method, which is expected to be expanded in the electrode fabrication of various organic secondary batteries with π-conjugated components.