Sodium carboxymethylcellulose/MXene/zeolite imidazolium framework-67-derived 3D porous carbon aerogel for high-performance asymmetric supercapacitors.

ABSTRACT

Herein, we propose a carbon/TiO2/Co3O4 (CTC) composite carbon aerogel with a 3D porous conductive network structure derived from sodium carboxymethylcellulose (CMC)/Mxene (Ti3C2Tx)/zeolite imidazolium framework-67 (ZIF-67). Among them, CMC is used as the carbon skeleton, which can reduce the powdering caused by volume change and improve the cycle stability. Ti3C2Tx acts as the conductive agent and dispersant for ZIF-67, exposing more reactive sites while constructing fast conductive channels to enhance electrochemical performance. The microstructure of the CTC carbon aerogel is modulated by controlling the mass ratio of Ti3C2Tx to ZIF-67, and the carbon aerogel with a mass ratio of 23 (CTC-23) is experimentally demonstrated to have the best electrochemical performance. The CTC-23 electrode exhibits a high specific capacitance of 481.7 F g-1 at 1 A g-1 and possesses a rate performance of 78.9 % at 10 A g-1. The assembled asymmetric supercapacitor (ASC, CTC-23//Ti3C2Tx) delivers an energy density of 48.4 Wh kg-1 at a power density of 699.8 W kg-1. Moreover, the ASC device maintains 85.3 % initial capacitance and 99.1 % coulombic efficiency after 10,000 GCD cycles, indicating good cycling stability. This facile design pathway provides a new insight for the development of high-performance electrode materials.