Temperature-dependent pseudocapacitive behaviors of polyaniline-based all-solid-state fiber supercapacitors

Abstract

The work temperatures have a crucial influence on the performance of supercapacitors. However, temperature effects on pseudocapacitive behaviors are rarely studied for flexible high-performance fiber supercapacitors. Herein, we systematically investigated the electrochemical responses of all-solid-state fiber-based supercapacitors composed of carbon nanotube fiber (CNF) electrodes decorated with porous carbon nanotubes (CNTs)/polyaniline (PANI) and gel electrolyte at various ambient temperatures between −5 °C and 55 °C. The results show that the capacitance of the supercapacitor first enhances with the rising temperature under 40 °C and declines at 55 °C. The internal resistance presents a gradual downward trend and the self-discharge behavior accelerates at high operating temperatures. CNTs/PANI-modified flexible fiber supercapacitors are also far from unsatisfactory for cycling stability tests in a high-temperature environment. After experiencing 5000 charge–discharge cycles at 55 °C, the capacitance retains only 43.86 %, far below the counterpart at low temperatures. This study provides a fundamental comprehension of the temperature dependence of pseudocapacitive behaviors of PANI-based fiber supercapacitors.

Keywords

• Thermal effect
• Polyaniline
• Carbon nanotube fibers
• Fiber supercapacitors
• Pseudocapacitive behaviors