Polyaniline-filled carbonized wood membrane as an advanced self-supported electrode for superior pseudocapacitive energy storage

Abstract Integrating electrochemical redox-active materials with 3D conductive scaffolds holds high promise to the development of high-performance energy storage devices. Herein, a self-supported, hierarchically porous polyaniline (PANI)-filled carbonized wood membrane (CWM@PANI) electrode is rationally designed and fabricated for high-performance pseudocapacitors. The synthetic strategy, engaging a controllable in situ electropolymerization, enables a uniform deposition of PANI particles on the porous wall of the aligned microchannels of the CWM to form a structurally integrated heterostructure. The aligned open microchannels inside the CWM favor unimpeded and continuous supply of electrolyte to the anchored PANI particles. Moreover, the uniformly distributed PANI particles contribute maximum volume to participate in the redox reactions. As a result, measured with three-electrode configuration at 0.5 A g−1, the as-fabricated CWM@PANI electrode with a high PANI loading (6.0 mg cm−2) delivers gravimetric and areal capacitances of 639.5 F g−1 and 3837 mF  cm−2, respectively, as well as good rate capacity (369.8 F g−1 at 10 A g−1) and excellent cycling stability (88.5% capacitance retention after 5000 cycles). Furthermore, a maximum energy density of 43.11 Wh kg−1 at a power density of 350 W kg−1 is also achieved. This work presents an effective strategy to fabricate a high-performance self-supported electrode as a promising alternative of its powdery counterparts for practically applicable supercapacitor devices.