Unique Core–Shell Nanorod Arrays with Polyaniline Deposited into Mesoporous NiCo2O4 Support for High-Performance Supercapacitor Electrodes

Abstract

Polyaniline (PANI), one of the most attractive conducting polymers for supercapacitors, demonstrates a great potential as high performance pseudocapacitor materials. However, the poor cycle life owing to structural instability remains as the major hurdle for its practical application; hence, making the structure-to-performance design on the PANI-based supercapacitors is highly desirable. In this work, unique core-shell NiCo2O4@PANI nanorod arrays (NRAs) are rationally designed and employed as the electrode material for supercapacitors. With highly porous NiCo2O4 as the conductive core and strain buffer support and nanoscale PANI layer as the electrochemically active component, such a heterostructure achieves favorably high capacitance while maintaining good cycling stability and rate capability. By adopting the optimally uniform and intimate coating of PANI, the fabricated electrode exhibits a high specific capacitance of 901 F g(-1) at 1 A g(-1) in 1 M H2SO4 electrolyte and outstanding capacitance retention of ∼91% after 3000 cycles at a high current density of 10 A g(-1), which is superior to the electrochemical performance of most reported PANI-based pseudocapacitors in literature. The enhanced electrochemical performance demonstrates the complementary contributions of both componential structures in the hybrid electrode design. Also, this work propels a new direction of utilizing porous matrix as the highly effective support for polymers toward efficient energy storage.