Novel egg white gel polymer electrolyte and a green solid-state supercapacitor derived from the egg and rice waste

Highlights: • This is the first investigation on egg and rice waste as solid supercapacitor. • An environmental friendly method for producing EW-GPE is proposed. • The green EW-GPE can provide superior ionic conductivity and durability. • The EW-GPE shows good interaction with rice husk AC electrodes. • The supercapacitor possesses an excellent capacitance and high flexibility. Herein, we fabricate a novel egg white gel polymer electrolyte and green solid-state supercapacitor for the first time, by utilizing broken eggshell and rice husks, the biomaterials of egg and rice waste. Taking advantages of the high affinity between the egg white and eggshell membranes and the optimization of electrolyte salt, the fabricated novel egg white gel polymer electrolyte combines several advantages such as high ionic conductivity, high electrolyte retention, adequate mechanical properties and thermal stability, and environmental friendliness. Furthermore, profit from the significantly electrolyte retention and improved contact between EW-GPE and the rice husk based activated carbon electrodes, the resulting green solid-state supercapacitor exhibits high flexibility, good electrochemical properties (i.e., high specific capacitance of 214.3 F g⁻¹ at 0.2 A g⁻¹ and 204.4 F g⁻¹ at 1 A g⁻¹) and stable cycle performance. In addition, the present investigation of a green gel polymer electrolyte and solid-state supercapacitor opens new avenues towards using low-cost daily waste biomaterials in new energy storage devices.