Interfacial growth of free-standing PANI films: toward high-performance all-polymer supercapacitors

Abstract

Along with high power capability and energy density, long cycle life is regarded an essential performance requirement for energy storage devices. The rapid capacitance decline of conducting polymer-based electrodes remains a major technical challenge and precludes their practical applications in supercapacitors. In this work, a polyaniline (PANI) network is synthesizedviainterfacial Buchwald-Hartwig polymerization for the first time, facilitating the construction of covalently connected PANI networks by ligand-promoted C-N bond formation. Particularly, the interfacial synthesis and subsequent gas release from pre-anchored protecting groups allow bottom-up and efficient access to porous cross-linked PANI (PCL-PANI) films that are free-standing and solvent-resistant. Upon assembling into supercapacitors, the PCL-PANI material enables an unprecedent long-term charge-discharge cycling performance (>18 000 times) without clear capacitance loss for an additive-free pseudocapacitive system. In addition, this synthesis affords electrodes entirely consisting of conducting polymers, yielding highly reversible gravimetric capacitance at 435 F gelectrode−1in a two-electrode system, and a high gravimetric energy of 12.5 W h kgelectrode−1while delivering an outstanding power density of 16 000 W kgelectrode−1, which is 10-fold higher than those of conventional linear PANI composite supercapacitors. This synthetic approach represents a novel and versatile strategy to generate additive/binder-free and high-performance conducting thin-films for energy storage.