Facile in Situ Synthesis of Multiple-Heteroatom-Doped Carbons Derived from Polyimide Precursors for Flexible All-Solid-State Supercapacitors

Efficient strategies to prepare carbon materials with improved electrochemical performance for supercapacitors have been in great demand. Herein, we develop multiple-heteroatom-doped carbons (from single- to triple-doped) by pyrolysis of polyimide precursors using a facile in situ approach. This approach can be used to tune heteroatom compositions by controlling the desired polyimide monomer functional groups as well as introducing external doping sources into the polyimide precursor solutions. Various types of multiple-heteroatom-doped carbons such as N; N,S-; N,F-; N,S,B-; and N,F,B-doped carbons are synthesized. Among these synthesized multiple-heteroatom-doped carbons, the specific capacitance of N,F,B triple-doped carbon exhibits 350.3 F g–1 at 1 A g–1 in a three-electrode system. Furthermore, a flexible all-solid-state supercapacitor device using the N,F,B-doped carbon with poly­(vinyl alcohol)–1 M H2SO4 gel electrolyte demonstrates a volumetric energy density of 0.58 mW h cm–3. It is expected that this synthesis strategy for multiple-heteroatom-doped carbons can be used for practical supercapacitor applications.