Polyaniline combining with ultrathin manganese dioxide nanosheets on carbon nanofibers as effective binder-free supercapacitor electrode
Shaoyun Chen, Yuanfang Zhang, Tian Du, Qingliang You, Min Zhong, Chenglong Hu, Jian Chen
Abstract
The binder-free supercapacitors were fabricated from polyaniline (PANI)@MnO 2 @flexible carbon nanofibers (CNFs) composite flexible electrodes. The flexible electrodes were constructed using a layer-by-layer synthetic strategy: a large-area MnO 2 ultrathin nanosheets firstly grew onto the surface of CNFs by self-decomposition of KMnO 4 , and then the PANI was in-situ coated on MnO 2 ultrathin nanosheets in turn through a dilute-solution polymerization to form PANI@MnO 2 @CNFs ternary electrode. In PANI@MnO 2 @CNFs electrode, the two-dimensional sheet-like structure provided by the PANI@MnO 2 nanosheets could be served as a high specific surface area and electrically conductive network for fast transport of electrolyte ions and electrons in the reaction, where PANI and MnO 2 were high-performance supercapacitor electrode materials. The specific capacitance of single PANI@MnO 2 @CNFs electrode was 654 F/g at the scan rate of 10 mV/s in Na 2 SO 4 electrolyte, and the capacitance retention was about 88.8% after 1000 cycles. Furthermore, the as-prepared symmetric supercapacitor with a PVA/Na 2 SO 4 gel electrolyte exhibited the maximum energy density of 27.9 Wh/kg at the power density of 400 W/kg, which was superior or similar to previously reported values of PANI-based supercapacitor. The as-prepared supercapacitors exhibited good electrochemical performance and high flexibility, which was a meaningful exploration for the application of flexible electrodes in the production of multi-element electrode materials for supercapacitors.