Electrospun TiO2 nanofiber electrodes for high performance supercapacitors

Nanofibers are one dimensional (1D) nanoarchitecture materials having high surface-to-volume ratio which provides improved ion diffusion and high mechanical strength to prevent volume expansion during electrochemical process and enhance the cycle stability. In the present study, TiO2 nanofibers (TNFs) were successfully synthesized on an aluminum collector with a polymer concentration of 9 wt % by cost-effective electrospinning technique followed by annealing at a temperature 500 °C. The XRD spectrum of electrospun TNFs exhibited predominant (101) orientation corresponding to anatase TiO2 with I41/amd symmetry. The estimated average crystallite size is 18 nm. The strongest Raman vibrational mode at 143 cm−1 confirms the phase purity of TNFs. The surface morphological feature depicts interconnected network fibers with a variation in the fiber diameter and the estimated average diameter is ∼150 20 nm. Very smooth surface and homogenously distributed ultra long nanofibers are observed from TEM analysis. The newly fabricated TNF electrode delivered a specific capacitance of 75 Fg−1 and retained 95% capacitance even after 5000 cycles. Moreover, it exhibited energy density and power density values of 24 Whkg−1 and 22.08 Wkg−1 respectively. The large capacitance, high coulombic efficiency and good structural stability demonstrate that TNFs should open up new opportunities for the next-generation high performance supercapacitors.