Intercalation of Small Organic Molecules into Ti₃C₂T_x MXene Cathodes for Flexible High‐Volume‐Capacitance Zn‐Ion Microsupercapacitor

Abstract

2D MXene materials based flexible miniaturized energy storage devices, such as the battery, [4,5] microsupercapacitors (MSCs), [6,7] hybrid metal-ion MSC, [8,9] are being extensively explored owing to their outstanding electrical conductivity, excellent mechanical stability, and versatile chemistry. [10] Considering MXene-based flexible miniaturized MSCs catering to integrated wearable electronics, the strong security, long cycling, and high energy density should be satisfied simultaneously. The emergence of hybrid multivalent metal cations Zn 2+ MSC using MXene cathodes fits well to the required conditions due to the co-contribution of both capacitive-type ion adsorption or fast surface redox reactions and diffusioncontrolled Faradic reactions originating from SCs and battery, respectively. [11] Moreover, the low cost, abundant sources, high safety, and eco-friendly features of Zn as compared to other alkaline metal ions like Li + , Na + , K + , Ca 2+ , and Mg 2+ enable the hybrid Zn-ion MSCs to be widely investigated. [12] Intercalation and delamination are necessary processes to obtain 2D MXene materials, [13] in which the MXene' interlayers will accommodate various ions and small organic molecules, resulting in adjustable interlayer spacing and unique properties. [14] The interlayer space usually affects the metal ion shuttles, larger space between MXene layers leads to the fast and easy diffusion of metal ions and helps achieve advanced electrochemical performance, which is particularly evident in metal ions with large radius. [15] Zn ion falls right into the alkaline metal ions with a large radius, almost twice as extensive as that of Li + (0.76 Å). Therefore, the high-performance MXene cathode-based Zn-ion MSC depends primarily on the appropriate selection of intercalators for MXene. In addition, the suitable intercalations could improve the high dispersion of MXene materials, which benefits the fabrication of MSC devices and reduce the resistance of the assembled Zn-ion MSC.Aimed at finding appropriate intercalators to achieve high-performance MXene cathodes based Zn-ion MSC, we delaminated 2D Ti 3 C 2 T x MXene using N,N-dimethylacetamide (DMAC) containing amide group, acetonitrile (ACN) containing cyanide group, Dimethyl sulfoxide (DMSO) containing sulfinyl group, N,N-dimethylformamide (DMF) containing The delamination of 2D Ti 3 C 2 T x 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-ionbased energy storage device because of the different radii of metal ions such as Li + , Na + , Mg 2+ Zn 2+ , etc. Herein, the intercalation of N,N-dimethylacetamide (DMAC), acetonitrile (ACN), dimethyl sulfoxide (DMSO), LiCl (H 2 O) into Ti 3 C 2 T x cathodes and their electrochemical performance comparisons by fabricating Zn-ion microsupercapacitors (MSCs) is reported. Studies found that an increa...

Capacitance-Enhanced Microsupercapacitors with a Redox Electrolyte Additive for an All-MXene-Based Flexible Self-Powered Integrated Photodetecting System

“…After centrifugation at 12000 rpm for 8 min, the black colloidal solution (Ti 3 C 2 T x -DMAC) was collected and diluted with DMAC to a concentration of 2 mg mL –1 for later use. Ti 3 C 2 T x -DCTES MXene (1 mg mL –1 ) was prepared by dispersing 1 g of multilayer Ti 3 C 2 T x MXene into 15 mL of DCTES solution using the same delamination and collection method …”

“…Ti 3 C 2 T x -DCTES MXene (1 mg mL −1 ) was prepared by dispersing 1 g of multilayer Ti 3 C 2 T x MXene into 15 mL of DCTES solution using the same delamination and collection method. 15 2.3. Preparation of Zn Anode Solutions and Gel Electrolytes.…”

“…The excellent performance of the fabricated MSCs is confirmed by the large layer spacing between the Ti 3 C 2 T x -DMAC nanosheets, the very small positive and negative channels, and the large number of defects introduced by the spraying method. 15 K 3 Fe(CN) 6 is a very attractive electrolyte additive with an iron ion (Fe 3+ ) as the central atom, cyanogen ion (CN − ) as the ligand, ferric cyanogen ion {[Fe(CN) 6 ] 3− } as its inner boundary, and potassium ion (K + ) as its outer boundary. 16 The free K + can improve the conductivity of electrolytes in the solid state structure and contribute to the formation of doublelayer capacitance.…”

A Ti3C2Tx MXene cathode and redox-active electrolyte based flexible Zn-ion microsupercapacitor for integrated pressure sensing application

“…Zn-ion hybrid microsupercapacitors (MSCs) have been widely explored because they combine the high energy density of batteries with the high power density of SCs. 1 2D transition metal carbides, carbonitrides, and nitrides (MXenes) have gradually become advantageous for use as the functional cathodes of Zn-ion hybrid MSCs, [2][3][4] due to their special adjustable physical and chemical properties. In the fabrication of 2D MXene materials, the selection of an intercalator will directly affect the crystal structure, atomic defects, layer spacing and surface functional groups of the synthesized MXene, and they further have effects on its physical and chemical properties.…”

A Thermally Chargeable Supercapacitor based on the g‐C3N4‐Doped PAMPS/PAA Hydrogel Solid Electrolyte and 2D MOF@Ti3C2Tx MXene Heterostructure Composite Electrode

“…[16][17] As for electrode materials, 2D Ti 3 C 2 T x MXene has been widely used in the field of electrochemical energy storage because of its highly reversible surface redox reactions, remarkable electrical conductivity, acidic and chemical stability. [18][19] However, Ti 3 C 2 T x MXene suffers from the weaker active sites on its surface, resulting in a low energy density. 2D metalorganic framework (MOF) composed of metal cations (or metal clusters) and organic connectors is especially suitable for highperformance electrode materials due to the extremely large specific surface area, easily adjustable pore size, and abundant pseudocapacitive redox sites.…”