Hierarchical double-shelled poly(3,4-ethylenedioxythiophene) and MnO2 decorated Ni nanotube arrays for durable and enhanced energy storage in supercapacitors

Abstract

As an attractive supercapacitor material, MnO2 greatly suffers poor conductivity and unsatisfied stability. In this work, double-shelled poly(3,4-ethylenedioxythiophene) (PEDOT) and MnO2 decorated Ni nanotube arrays (NTAs) are successfully synthesized by a simple electrodeposition strategy, endowing the hybrid with remarkably improved conductivity and prolonged durability. As a self-supported electrode, the resulting PEDOT@MnO2@NiNTAs exhibits outstanding electrochemical properties, including high mass capacitance (based on MnO2 mass, 442.85 F g−1 at 2.5 A g−1) and excellent cycling stability (80.37% capacitance retention after 15000 cycles). Furthermore, when assembling an asymmetric supercapacitor with the PEDOT@MnO2@NiNTAs and activated carbon (AC), the device affords a voltage window up to 1.7 V and delivers a large volumetric capacitance (1.47 F cm−3 at 4 mA cm−3) and high energy density (0.59 mWh cm−3 at power density of 84.96 mW cm−3), indicating its great potential in practical supercapacitor applications.