Electrospun TiO2 nanofiber electrodes for high performance supercapacitors

Abstract

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, TiO _2 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 TiO _2 with I4 _1 /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.

Keywords

• 1D nanoarchitecture materials
• electrospinning technique
• TiO2 nanofibers (TNFs)
• high performance supercapacitors