Lithium ion conducting Cardiospermum halicacabum bio-electrolytes for electric double layer capacitor and lithium ion conducting cell applications

Abstract

Cardiospermum halicacabum (C.halicacabum), commonly known as balloon vine, a medicinal herb is investigated as a electrolytic material for all solid state batteries and supercapacitor applications in this research. C.halicacabum – lithium nitrate (LiNO₃), a new bio-electrolyte system is developed by adopting a solution casting technique, and the effect of LiNO₃ of varied amount (0.6 wt % to 1.0 wt %) on the electrolytic system is analyzed. The mandatory requisite of amorphous phase in electrolyte is ensured with an X-ray diffraction study and the interaction between host and salt material is explored by means of Fourier -Transform infrared (FTIR) study. Electrochemical impedance analysis (EIS) detects the diminishing resistive behavior with increasing amount of salt in the host material of C.halicacabum and the highest ionic conductivity value achieved is 7.02 × 10⁻³ S cm⁻¹ with the addition of 0.9 wt% of LiNO₃ with the host material. Electric double layer capacitor (EDLC) is constructed with the best conducting membrane as electrolyte. The Cyclic voltammetry (CV) results show the maximum specific capacitance of 166.67 F/g and the Galvanostatic charge –discharge (GCD) study shows the assembled EDLC is able to offer a high power density of 6250 WKg^-1 at a current density of 50 mA/g. Also, GCD ensures the cyclic stability of the synthesized membrane. Additionally, lithium ion conducting cell is fabricated with the best conducting membrane and the output of 1.7 V is obtained with a good stability. All these results recommend the chosen biomaterial is a potential candidate in energy storage applications.