One-pot preparation of highly porous paddy waste derived-cellulose-silica nanocomposite membrane separator for advanced performances of supercapacitor

A new strategy was demonstrated to produce cellulose nanofibril-silica (CNF-SiO2) nanocomposite membrane separator for supercapacitor by one-pot synthesis of silica (SiO2) nanoparticles using different contents of tetraethyl orthosilicate (TEOS) precursor (0.9, 1.8, 2.7, 3.6 wt%). With the SiO2 nanoparticles acting as the disassembling agent, a highly porous CNF-SiO2 nanocomposite membrane was prepared using a simple solvent casting method. The CNF-SiO2 nanocomposite membrane with 1.8 wt% TEOS content (CNF-C2), exhibited the best properties with high porosity of 61%, electrolyte uptake ability of 260% and ionic conductivity of 5.0 mS cm(- 1). Besides, the maximum thermal degradation temperature (T-max) of the CNF-SiO2 nanocomposite membrane increased from 300 ? to 322 ?, making it suitable for use within the operating temperatures of a supercapacitor. A symmetric supercapacitor assembled with CNF-C2 separator achieved the highest specific capacitance of 179.0 F g(- 1) at 0.1 A g(- 1) and energy density of 35.8 Wh kg(- 1) at a power density of 240.0 W kg(- 1). This CNF-SiO2 nanocomposite membrane helped the supercapacitor to achieve excellent electrochemical stability after 10,000 charge-discharge cycles with a capacitance retention and coulombic efficiency of 98.3% and 95.0%, respectively. The presented results proved that the CNF-SiO2 nanocomposite membrane is a good alternative separator in the supercapacitor application. (GRAPHICS)

Automated summary

A cellulose nanofibril-silica nanocomposite membrane separator for supercapacitor was successfully synthesized using a one-pot method. The membrane showed excellent electrochemical properties and proved to be a good alternative separator for supercapacitor application.