Page 145 - Read Online

Zheng et al. Soft Sci. 2026, 6, 32 Page 35 of 57

alcohol (PVA), poly (ethylene oxide), polyacrylonitrile (PAN), or chitosan. MXene layers are usually encased
or embedded in ultrafine fibers during this process, creating three-dimensional fiber networks with high
specific surface area. Ion adsorption and surface Faraday reactions are made easier by this shape, suggesting
possible uses in flexible electrodes and sensing. Figure 12D shows a schematic of the procedure. However,
[151]
traditional electrospinning confronts two key obstacles when manufacturing fibers with high MXene
content. On one hand, MXene’s high conductivity causes rapid charge dissipation in the spinning jet, leading
to process instability or even short circuits. However, MXene has a tendency to aggregate in the polymer
matrix, especially at high concentrations, which makes uniform dispersion challenging. This limits
electrochemical accessibility and overall conductivity by producing non-uniform fiber shape and bead-like
features [Figure 12E] .
[148]
Researchers have created a number of cutting-edge methods to get around these restrictions. By substituting
a solidification bath for the traditional collector, Levitt et al.’s “one-step bath electrospinning” technique [149]
stabilizes the jet process of highly conductive spinning solutions [Figure 12F]. Creating core-shell structures
is another tactic. In order to reduce reliance on intrinsic fiber conductivity while retaining flexibility, Shao
et al. built a core-shell architecture using conductive yarn as the core and MXene composite fibers as the
shell . Post-treatment of composite fibers is another important way to improve performance. Recently, Su
[152]
et al. introduced MXene into piezoelectric polymer devices [147] . They greatly increased fiber piezoelectric
responsiveness by promoting crystalline phase transitions and improving polarization through interactions
between MXene surface functional groups and polymer chains. Applications such as human motion
monitoring demonstrate the potential of this method [Figure 12G and H]. In the meantime, Chang et al.
successfully created composite fiber fabrics that combined mechanical stability and high photothermal
conversion efficiency by encasing MXene within a RC matrix [133] . These materials are appropriate for
solar-powered water evaporation and personal heat management due to their just 0.1 mm thickness. This
study provides new insights for creating multifunctional smart fabrics by demonstrating how encapsulation
structures efficiently protect MXene from environmental deterioration, improving its light absorption
capability and cycling stability in humid circumstances.

The double-winding approach
The double-winding method utilizes pre-fabricated stretchable CNT films as a scaffold and conductive
pathway to assemble nanomaterials like MXene, which are difficult to directly spin into macroscopically
continuous yarns [31,153] . Figure 12I depicts the process flow diagram, which consists of two essential steps.
First, using techniques like drop casting or impregnation, MXene dispersions are evenly deposited onto
stretched CNT films. Subsequently, the loaded films undergo mechanical twisting, causing them to
spiral-contract and consolidate into yarns. During this process, MXene nanosheets are effectively captured
and encapsulated within the helical internal voids or “corridors” formed by the CNT network [153] .
Cross-sectional and longitudinal SEM photos in Figure 12J show that successful confinement of MXene
layers within the yarn’s helical structure is confirmed by scanning electron microscopy examination. In order
to build high-performance fiber-based electrochemical devices, this architecture creates a special open
microenvironment. The CNT network offers continuous electronic conduction pathways and crucial
mechanical support, and the numerous interlayer voids enable quick electrolyte permeation and effective ion
transport .
[31]

The capacity to obtain exceptionally high active material loading (up to 95-98 wt%), which allows the
electrochemical performance of the composite yarn to approach that of pure MXene materials, is the
method’s greatest benefit. Research shows that the resulting MXene/CNT composite yarn has exceptional
energy storing properties. For example, the double-wound yarn supercapacitor described by Wang et al.
fared better in specific capacitance, energy density, and power density than the majority of modern