Exploring the Functional Properties of Sodium Phytate Doped Polyaniline Nanofibers Modified FTO Electrodes for High-Performance Binder Free Symmetric Supercapacitors

The performance of high-rate supercapacitors requires fine morphological and electrical properties of the electrode. Polyaniline (PANI), as one of the most promising materials for energy storage, shows different behaviour on different substrates. The present study reports on the surface modification of fluorine doped tin oxide (FTO) with the sodium phytate doped PANI without any binder and its utilization as a novel current collector in symmetric supercapacitor devices. The electrochemical behaviour of the sodium phytate doped PANI thin film with and without a binder on fluorine doped tin oxide (FTO) as current collector was investigated by cyclic voltammetry (CV). The electrode without a binder showed higher electrocatalytic efficiency. A symmetrical cell configuration was therefore constructed with the binder-free electrodes. The device showed excellent electrochemical performance with high specific capacities of 550 Fg−1 at 1 Ag−1 and 355 Fg−1 at 40 Ag−1 calculated from galvanostatic discharge curves. The low charge transfer and solution resistances (RCT and RS) of 7.86 Ωcm² and 3.58 × 10−1 Ωcm², respectively, and superior rate capability of 66.9% over a wide current density range of 1 Ag−1 to 40 Ag−1 and excellent cycling stability with 90% of the original capacity over 1000 charge/discharge cycles at 40 Ag−1, indicated it to be an efficient energy storage device. Moreover, the gravimetric energy and power density of the supercapacitor was remarkably high, providing 73.8 Whkg−1 at 500 Wkg−1, respectively. The gravimetric energy density remained stable as the power density increased. It even reached up to 49.4 Whkg−1 at a power density of up to 20 Wkg−1.