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Page 48 of 57 Zheng et al. Soft Sci. 2026, 6, 32

Crucial technologies for fabrication
High-performance graphene/MXene hybrid fibers are built using a cross-scale structural design approach
that synchronizes synergistic interactions at the macroscopic level as well as at the molecular level. In order
to overcome the inherent trade-offs between mechanical strength, electrical conductivity, and
electrochemical activity, effective hybridization requires precise management of interfacial chemistry,
nanoscale design, and microstructure. The multiscale design principles and interfacial synergistic processes
controlling the performance of graphene/MXene composite fibers are methodically broken down in this
section.

Interfacial bonding and charge/stress transfer mechanisms
The essential area for charge carrier exchange and mechanical stress is the interface between graphene (or
GO) and MXene. Depending on the type of interfacial bonding, synergistic mechanisms can be identified.
The lowest interfacial temperature resistance and the strongest stress transfer capabilities are provided by
covalent bonding. For example, conjugated covalent bridging structures are created at the margins of GO by
the amidation reaction between amine-functionalized polymers and carboxyl groups, which simultaneously
improves electrical conductivity and tensile strength [63] . Similarly, carbonization-treated
polydopamine-coated MXene/GO composites produce nitrogen-doped carbon bridge structures that
significantly improve material mechanical integrity and rate performance . Multivalent cations (Ca , Mg ,
2+
[177]
2+
NH ) are used in ionic crosslinking as “ionic bridges” between surface negative functional groups (-COO , -
+
4
-O ) on GO or MXene. This technique adds reversible sacrificial bonds to increase toughness in addition to
-
densifying fibers by removing interlayer vacancies [38,145,178] . In hydrated GO/MXene complexes, hydrogen
bonding is common. Constrained water molecules create ordered hydrogen-bond networks between
neighboring nanosheets, preserving parallel orientation throughout gelation and drying, according to Yang
et al. . This important discovery helps to reduce internal flaws. π-π interactions take center stage when
[36]
conjugated polymers (like PEDOT:PSS) or CNTs are added. The otherwise limited out-of-plane charge
transfer in vertically aligned two-dimensional sheets is enhanced by these interactions, which create
continuous electronic channels at heterogeneous interfaces [176,177] .

Nanoscale organization: pore volume, stacking, and orientation
The anisotropic properties of the fiber are determined at the nanoscale by the arrangement of individual
nanosheets. Three basic structural patterns have been identified: in-plane conductivity and modulus are
maximized by parallel alignment along the fiber axis. Shear-induced orientation during wet spinning, which
is frequently aided by liquid crystal spinning slurries, is how this structure is accomplished . This design is
[15]
further optimized by large-small flake hybridization, in which smaller GO flakes fill interstitial spaces to
increase density and decrease electron scattering, while bigger flakes form a continuous directed
framework [15,50] . Aligned transversely to the fiber axis, perpendicular orientation creates open nanoconductive
routes that facilitate quick ion transport, which is essential for high-rate electrochemical energy storage.
Guan et al. showed that plug flow preserves this metastable structure by removing destructive shear
pressures, but expansive flow in microchannels creates tensile stress and flips nanosheets into vertical
alignment . Three-dimensional electrical pathways are created by overcoming the interlayer conductivity
[176]
restrictions of two-dimensional materials by inserting CNTs as bridges between layers [Figure 15C].
Functional spatial separation is achieved by heterogeneous layered and core-shell structures: highly
conductive cores (like MXene/CNT) guarantee effective electron transport along the fiber axis, while
functional or protective shells (like GO, ANF, and PU) offer environmental barriers, mechanical
reinforcement, or extra pseudocapacitive effects [122,175] . Enhanced SAXS orientation factors [175] confirm that
the shell layer’s spatial confinement effect also encourages core ordering during coaxial spinning.