skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: 4D printing of MXene hydrogels for high-efficiency pseudocapacitive energy storage
Abstract 2D material hydrogels have recently sparked tremendous interest owing to their potential in diverse applications. However, research on the emerging 2D MXene hydrogels is still in its infancy. Herein, we show a universal 4D printing technology for manufacturing MXene hydrogels with customizable geometries, which suits a family of MXenes such as Nb 2 CT x , Ti 3 C 2 T x , and Mo 2 Ti 2 C 3 T x . The obtained MXene hydrogels offer 3D porous architectures, large specific surface areas, high electrical conductivities, and satisfying mechanical properties. Consequently, ultrahigh capacitance (3.32 F cm −2 (10 mV s −1 ) and 233 F g −1 (10 V s −1 )) and mass loading/thickness-independent rate capabilities are achieved. The further 4D-printed Ti 3 C 2 T x hydrogel micro-supercapacitors showcase great low-temperature tolerance (down to –20 °C) and deliver high energy and power densities up to 93 μWh cm −2 and 7 mW cm −2 , respectively, surpassing most state-of-the-art devices. This work brings new insights into MXene hydrogel manufacturing and expands the range of their potential applications.  more » « less
Award ID(s):
2041050
PAR ID:
10396131
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ;
Date Published:
Journal Name:
Nature Communications
Volume:
13
Issue:
1
ISSN:
2041-1723
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract MXenes constitute a rapidly growing family of 2D materials that are promising for optoelectronic applications because of numerous attractive properties, including high electrical conductivity. However, the most widely used titanium carbide (Ti3C2Tx) MXene transparent conductive electrode exhibits insufficient environmental stability and work function (WF), which impede practical applications Ti3C2Txelectrodes in solution‐processed optoelectronics. Herein, Ti3C2TxMXene film with a compact structure and a perfluorosulfonic acid (PFSA) barrier layer is presented as a promising electrode for organic light‐emitting diodes (OLEDs). The electrode shows excellent environmental stability, highWFof 5.84 eV, and low sheet resistanceRSof 97.4 Ω sq−1. The compact Ti3C2Txstructure after thermal annealing resists intercalation of moisture and environmental contaminants. In addition, the PFSA surface modification passivates interflake defects and modulates theWF. Thus, changes in theWFandRSare negligible even after 22 days of exposure to ambient air. The Ti3C2TxMXene is applied for large‐area, 10 × 10 passive matrix flexible OLEDs on substrates measuring 6 × 6 cm. This work provides a simple but efficient strategy to overcome both the limited environmental stability and lowWFof MXene electrodes for solution‐processable optoelectronics. 
    more » « less
  2. Abstract 3D continuous mesoscale architectures of nanomaterials possess the potential to revolutionize real‐time electrochemical biosensing through higher active site density and improved accessibility for cell proliferation. Herein, 3D microporous Ti3C2TXMXene biosensors are fabricated to monitor antibiotic release in tissue engineering scaffolds. The Ti3C2TX‐coated 3D electrodes are prepared by conformal MXene deposition on 3D‐printed polymer microlattices. The Ti3C2TXMXene coating facilitates direct electron transfer, leading to the efficient detection of common antibiotics such as gentamicin and vancomycin. The 3D microporous architecture exposes greater electrochemically active MXene surface area, resulting in remarkable sensitivity for detecting gentamicin (10–1 mM) and vancomycin (100–1 mM), 1000 times more sensitive than control electrodes composed of 2D planar films of Ti3C2TXMXene. To characterize the suitability of 3D microporous Ti3C2TXMXene sensors for monitoring drug elution in bone tissue regeneration applications, osteoblast‐like (MG‐63) cells are seeded on the 3D MXene microlattices for 3, 5, and 7 days. Cell proliferation on the 3D microporous MXene is tracked over 7 days, demonstrating its promising biocompatibility and its clinical translation potential. Thus, 3D microporous Ti3C2TXMXene can provide a platform for mediator‐free biosensing, enabling new applications for in vivo monitoring of drug elution. 
    more » « less
  3. Abstract Lightweight energy storage devices are essential for developing compact wearable and distributed electronics, and additive manufacturing offers a scalable, low‐cost approach to fabricating such devices with complex geometries. However, additive manufacturing of high‐performance, on‐demand energy storage devices remains challenging due to the need for stable, multifunctional nanomaterial inks. Herein, the development of 2‐dimensional (2D) titanium carbide (Ti3C2TxMXene) ink that is compatible with aerosol jet printing for energy storage applications is demonstrated. The developed MXene ink demonstrates long‐term chemical and physical stability, ensuring consistent printability and achieving high‐resolution prints (≈45 µm width lines) with minimal overspray. The high‐resolution aerosol‐jet printed MXene supercapacitor achieves an areal capacitance of 122 mF cm−2and a volumetric capacitance of 611 F cm−3, placing them among the highest‐performing printed supercapacitors reported to date. These findings highlight the potential of aerosol jet printing with MXene inks for on‐demand, scalable, and cost‐effective fabrication of printed electronic and electrochemical devices. 
    more » « less
  4. null (Ed.)
    Abstract Here we report for the first time that Ti 3 C 2 T x /polymer composite films rapidly heat when exposed to low-power radio frequency fields. Ti 3 C 2 T x MXenes possess a high dielectric loss tangent, which is correlated with this rapid heating under electromagnetic fields. Thermal imaging confirms that these structures are capable of extraordinary heating rates (as high as 303 K/s) that are frequency- and concentration-dependent. At high loading (and high conductivity), Ti 3 C 2 T x MXene composites do not heat under RF fields due to reflection of electromagnetic waves, whereas composites with low conductivity do not heat due to the lack of an electrical percolating network. Composites with an intermediate loading and a conductivity between 10–1000 S m −1 rapidly generate heat under RF fields. This finding unlocks a new property of Ti 3 C 2 T x MXenes and a new material for potential RF-based applications. 
    more » « less
  5. Transition metal carbides (MXenes) are an emerging family of highly conductive two-dimensional materials with additional functional properties introduced by surface terminations. Further modification of the surface terminations makes MXenes even more appealing for practical applications. Herein, we report a facile and environmentally benign synthesis of reduced Ti 3 C 2 T x MXene (r-Ti 3 C 2 T x ) via a simple treatment with l -ascorbic acid at room temperature. r-Ti 3 C 2 T x shows a six-fold increase in electrical conductivity, from 471 ± 49 for regular Ti 3 C 2 T x to 2819 ± 306 S m −1 for the reduced version. Additionally, we show an enhanced oxidation stability of r-Ti 3 C 2 T x as compared to regular Ti 3 C 2 T x . An examination of the surface-enhanced Raman scattering (SERS) activity reveals that the SERS enhancement factor of r-Ti 3 C 2 T x is an order of magnitude higher than that of regular Ti 3 C 2 T x . The improved SERS activity of r-Ti 3 C 2 T x is attributed to the charge transfer interaction between the MXene surface and probe molecules, re-enforced by an increased electronic density of states (DOS) at the Fermi level of r-Ti 3 C 2 T x . The findings of this study suggest that reduced MXene could be a superior choice over regular MXene, especially for the applications that employ high electronic conductivity, such as electrode materials for batteries and supercapacitors, photodetectors, and SERS-based sensors. 
    more » « less