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Zhou et al. Soft Sci. 2026, 6, 10 Page 17 of 47

distribution, they enhanced rapid axial water diffusion, thereby improving overall output performance. To
further expand the design and application of flexible fiber-based hygroelectric devices, Sim et al. developed a
soft and elastic hygroelectric fiber (SEHF) using longitudinally asymmetrically oxidized MWNT
(Multi-Walled NanoTube) buckled fibers [135] . The fiber responds to changes in ambient humidity by
generating protons and facilitating their diffusion from oxidized CNT buckles to pristine CNT buckles.
Additionally, the SEHF exhibits an impressive strain capacity of up to 100%, providing greater elasticity and
softness compared to previously reported MEGTs .
[135]
2D structure
The 2D planar film-like structure offers clear advantages in humidity power generation layers, featuring a
large specific surface area that allows full contact with ambient moisture. Electrospun and non-woven fiber
films exhibit excellent flexibility and bendability, making them easily integrable into clothing or other
wearable devices. Polymer hydrogel films, with their internal cross-linked network structures, enable rapid
ion migration. When combined with fabric electrodes (such as carbon fiber cloth electrodes), the power
generation layer achieves both good flexibility and air permeability while maintaining electrical performance.
These advantages give 2D planar film structures broad application prospects in humidity-powered devices.

Fabric-based power generation layer films usually have abundant pores and transmission channels, which
facilitate ion migration. They are typically composed of electrospun fibers, bio-based fibers, or composite
fibers, and can also be fabricated by immersing non-woven fabrics in functional solutions. According to
different phase-structure designs, Han et al. reported a Van der Waals heterostructure based on textiles,
composed of conductive 1T phase tungsten disulfide@carbonized silk (1T-WS2@CSilk) and asymmetrically
distributed carbon black@cotton (CB@Cotton) fabrics [136] . The presence of Ocfgs enhances the proton
concentration gradient, improving the performance of high-performance wearable hydroelectric generators
(HEGs) [Figure 8A]. In this structure, the Al sheet serves as the top active electrode, the 1T-WS2@CSilk
fabric functions as the bottom inert electrode, and the CB@Cotton fabric forms the intermediate power
generation layer, enabling stable operation for over 10,000 s. As shown in Figure 8B, the research team first
surface-modified a nonwoven fabric substrate with CB, followed by precise coating of a PSSA/LiCl/GI/PVA
composite hydrogel onto predetermined areas . The resulting MEGT device enhances proton dissociation
[39]
efficiency through interactions between hygroscopic salts and the polyelectrolyte PSSA, driving efficient
charge output. To improve device multifunctionality, Chen et al. prepared a Janus heterogeneous film based
on electrospun nanofibers by directly growing one film on another . The film exhibits both moisture
[92]
absorption and evaporation capabilities, with two perforated electrodes made of different materials arranged
on opposite sides. Both layers are composed of nanofibers, whose abundant pores provide a large specific
surface area, enabling outstanding power output. To further increase performance, Xing et al. designed an
asymmetric nanofiber film combining hydrophilic PVA/PA with hydrophobic polyvinylidene fluoride
(PVDF) and produced a high-efficiency wearable MEGT . Using PA as a cross-linking agent, PVA
[91]
nanofibers form a gel-like structure that enhances structural stability under humid conditions, while the
asymmetric design ensures effective water circulation within the device. By leveraging the synergistic effects
of moisture absorption and ion migration in textiles, a MEGT for wearable systems was developed using safe
and environmentally friendly materials [Figure 8C] . PAAS served as the scaffold for water absorption and
[137]
ion migration, while sodium chloride incorporation improved ionic conductivity and increased current
output. As shown in Figure 8D, the MEGT device previously introduced achieves sustained
[98]
high-performance output through a vertically phase-engineered heteroelectrochemical bilayer. Its flexibility
and body-conforming design provide an excellent foundation for wearable MEGTs as integrated
self-powered devices.