Facile synthesis and super capacitive behavior of SWNT/MnO2 hybrid films

In this paper, facile and scalable single-walled carbon nanotubes with manganese oxide (SWNT/MnO₂) hybrid films are presented and systematically studied. The hybrid films are synthesized by a modified chemical vapor deposition (CVD) method, followed by one-step simple precipitation process and then characterized in 1 M tetraethylammonium tetrafluoroborate (TEABF₄)/propylene carbonate (PC) organic electrolyte. The electrochemical behavior of the SWNT/MnO₂ hybrid films is discussed with regards to specific capacitance, energy density, power capability and cycle life, by means of cyclic voltammetry measurements, electrochemical impedance analysis and galvanostatic charge/discharge analysis. The SWNT/MnO₂ hybrid electrode delivers highest specific capacitance of 150 F g⁻¹, energy density of 70 Wh kg⁻¹, and power density of 79 kW kg⁻¹. It exhibits excellent stability of 98.5% retention at current densities of 50 A g⁻¹ and 2 A g⁻¹, after 15,000 cycles and 1000 cycles, respectively. It also shows ultra-high frequency response with a knee frequency of 2043 Hz. The hybrid films are binder-free, robust, with pre-formed electrical pathways and excellent electrode structures for supercapacitor applications.

This paper was originally published in Nano Energy (2012) 1, 479.