Morphology and Dielectric Studies of Natural Fibers and PbO 2 Based Flexible Composite Sheets for Potential Energy Storage Applications

In this modern age of technology, flexible, light-weight, environment-friendly and low-cost electrodes are vastly feasible for applications in energy storage devices and disposable electronics. This study presents a comprehensive report on the morphological, dielectric, and impedance characteristics of lignocellulose (LC) fibers, PbO2, and LC/PbO2 sheets. The dielectric analysis shows that the dielectric constant depends on space charge polarization in the case of LC/PbO2 composite sheets. It can be concluded from impedance spectroscopy results that LC fibers show semiconductor-like behavior and fibers appear to consist of one type of dielectric species whose impedance behavior can be modeled by a parallel combination of a resistor and a capacitor. However, the impedance response of PbO2 consists of two types of dielectric species, which can be identified as grains and grain boundaries, both of which show a small temperature dependence. The impedance behavior of LC/PbO2 composite is different in comparison to individual LC fibers and PbO2. The presented study also reveals that impedance parameters of fabricated LC/PbO2 composites are temperature-independent, which might be due to counteracting the characteristics of LC fibers and PbO2 particles. This temperature-independence of the composite is important for their use in applications in flexible devices.