Intercalation of Small Organic Molecules into Ti3C2Tx MXene Cathodes for Flexible High‐Volume‐Capacitance Zn‐Ion Microsupercapacitor

Abstract

The delamination of 2D Ti3C2Tx MXene endows the injection of various ions and small organic molecules into its layers, thus leading to a tunable distance between layers and adjustable electrochemical properties. A suitable selection of intercalators needs to be considered according to the relevant metal‐ion‐based energy storage device because of the different radii of metal ions such as Li+, Na+, Mg2+ Zn2+, etc. Herein, the intercalation of N,N‐dimethylacetamide (DMAC), acetonitrile (ACN), dimethyl sulfoxide (DMSO), LiCl (H2O) into Ti3C2Tx cathodes and their electrochemical performance comparisons by fabricating Zn‐ion microsupercapacitors (MSCs) is reported. Studies found that an increased calculated interlayer space of 3.42, 7.47, 7.79, 8.3 Å is obtained for the H2O, DMSO, ACN, DMAC intercalated Ti3C2Tx cathodes, and a decreased calculated binding energy of −0.03, −0.78, −1.91, and −3.06 eV is obtained for the Ti3C2Tx‐H2O, Ti3C2Tx‐DMSO, Ti3C2Tx‐ACN, and Ti3C2Tx‐DMAC, respectively. The highest interlayer space, lowest binding energy, and amide groups make the DMAC intercalated Ti3C2Tx‐based MSC exhibit volumetric capacitance of 1873 F cm−3 at a scan rate of 5 mV s−1, much higher than 1103 F cm−3 for Ti3C2Tx‐H2O, 1313 F cm−3 for Ti3C2Tx‐ACN, 544 F cm−3 for Ti3C2Tx‐DMSO. The superior flexibility that results in invariable capacitance under 5000 bending cycles, together with the lighting test of the fabricated MSC, demonstrates its application in the wearable integrated system.