Abstract

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.

Graphical abstract

中文翻译：

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一锅法制备高多孔水稻废弃物衍生纤维素-二氧化硅纳米复合隔膜用于超级电容器的先进性能

摘要

通过使用不同含量的原硅酸四乙酯 (TEOS) 前体 (0.9, 1.8, 2.7)一锅法合成二氧化硅 (SiO 2 ) 纳米粒子，证明了一种新的策略来生产用于超级电容器的纤维素纳米纤维-二氧化硅 (CNF–SiO 2 ) 纳米_复合膜_隔膜, 3.6 重量％)。以SiO ₂纳米粒子作为分解剂，采用简单的溶剂浇注法制备了高孔隙度的CNF-SiO _{2纳米复合膜。}TEOS 含量为 1.8 wt% 的CNF-SiO ₂纳米复合膜 (CNF-C2) 表现出最好的性能，孔隙率高达 61%，电解质吸收能力为 260%，离子电导率为 5.0 mS cm − ¹. 此外， CNF-SiO ₂纳米复合膜的最大热降解温度（T _max ）从300℃提高到322℃，适合在超级电容器的工作温度范围内使用。用 CNF-C2 隔膜组装的对称超级电容器在 0.1 A g − ^{1 时实现了 179.0 F g − 1的}最高比电容，在240.0 W kg ^{− 1 的}功率密度下能量密度为 35.8 Wh kg ^{− 1}。这种 CNF-SiO ₂纳米复合膜帮助超级电容器在 10,000 次充放电循环后实现出色的电化学稳定性，电容保持率和库仑效率分别为 98.3% 和 95.0%。呈现的结果证明，CNF-SiO ₂纳米复合膜是超级电容器应用中良好的替代隔膜。

图形概要