A Gelation‐Assisted Approach for Versatile MXene Inks

Abstract

Due to outstanding electrical conductivity and excellent solution processing ability, MXenes show great potential as inks for printed/coated electronic devices. To meet the rheological requirements, an ultra‐high concentration is usually involved to formulate MXenes into versatile inks, however, low efficiency in rheology regulation, and restacking issues of MXene sheets hinder their further applications. Herein, a gelation‐assisted approach is proposed to prepare versatile MXene inks with a 3D interlinked network to well address above issues. With an effective combination of cross‐linking as well as the swelling of interlinked network, the gel ink exhibits tunable rheological properties by simply tuning the water amount within the sol‐gel system. Among various applicable printing/coating techniques ranging from painting to extrusion printing, blade coating is selected to demonstrate the advantage of MXene gel ink. The smooth coating layer with interlinked 3D structures is greatly beneficial to the uniform and dense zinc deposition with high reversibility, and endows the aqueous zinc ion batteries with a remarkable rate capability. This work provides an alternative approach to prepare versatile MXene inks and would offer MXenes new opportunities for their application in advanced printable electronic devices.

Enhancing the Chemical Stability of MXene Through Synergy of Hydrogen Bond and Coordination Bond in Aqueous Solution

“…Compared with MXene, the −OH peaks of MXene-Ala and MXene-Cys are red-shifted to 3446 and 3437 cm −1 , respectively, suggesting the hydrogen bonding between MXene nanosheets and the amino acid molecules. [35,36] In the Ti 2p spectrum of MXene-Cys (Figure 4b), a Ti 2p 3/2 peak is ascribed to Ti-S at 455.5 eV, indicating the successful binding of cysteine molecules to Ti 3 C 2 T x . [37,38] The S 2p spectrum of fresh MXene-Cys displays one significant S 2p 3/2 peak attributed to S-Ti-C at 163.6 eV (Figure S7, Supporting Information), which further verifies the successful binding of cysteine molecules.…”

“…Compared with MXene, the −OH peaks of MXene‐Ala and MXene‐Cys are red‐shifted to 3446 and 3437 cm −1 , respectively, suggesting the hydrogen bonding between MXene nanosheets and the amino acid molecules. [ 35,36 ]…”

Monolithically integrated flexible sensing systems with multi-dimensional printable MXene electrodes

“…The added crosslinker in MXene-based gels could assist them in forming a dynamic, recoverable 3D gel network and facilitate the gelation of printable nanocomposite ink without requiring organic dispersing or rheological agents, ultimately yielding a 3D and screen-printable gel with high viscosity and thixotropic characteristics. [40][41][42][43] In this study, various polyamines have been considered to bridge the MXene nanosheets in the aqueous printable inks. Both hexanediamine and tris(2-aminoethyl)amine solutions can promote similar gelation, as shown in Fig.…”

Non‐Monotonic Capacitance Change of Layered Ti3C2Tx MXene Film Structures under Increasing Compressive Stress

“…[ 9 ] Ti 3 C 2 T x MXenes exhibit quite potential in flexible devices, as they admit considerable energy density up to ≈100–450 F g −1 in aqueous electrolytes based on a pseudocapacitive redox mechanism. [ 9,10–13 ] Moreover, unlike other metal oxides or sulfides‐based pseudocapacitive materials such as MoS 2 , or MoO 3 , MnO 2 , [ 5,14–16 ] MXenes exhibit electrical conductivity and can form free‐standing film via simple vacuum‐assisted filtration [ 9 ] or other versatile shapes/structures via sorted printing techniques (inkjet printing, extrusion printing, screen printing, and 3D printing), [ 7,17–20 ] without the addition of conducting materials such as carbon nanotubes or graphene. Large‐scale fabrication of MXene films has also been developed.…”