Sweat-pumping cooling fabric for enhanced power generation and comfort

Zhu, Renbo; Zhang, Zhongliang; Luo, Yonghui; Yang, Jing; Liu, Su; Zhang, Yufei; Wang, LinGe; Tao, Xiaoming

doi:10.1038/s41467-026-70856-8

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Published: 24 March 2026

Sweat-pumping cooling fabric for enhanced power generation and comfort

Nature Communications volume 17, Article number: 4374 (2026) Cite this article

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Abstract

Energy harvesting devices are the critical components in the self-powered wearable microelectronic systems. However, insufficient electrical output limits their effectiveness as wearable power supplies, and poor moisture/thermal management often causes discomfort, particularly with sweat release. Here, we report a self-powered, self-cooling fabric that not only enhances electrical output but also actively improves wear comfort by pumping out sweat through directional water transport. This synergistic effect of water removal and ion migration enables simultaneous electricity generation and cooling. The fabric was rationally designed to balance power output with comfort: water evaporation on the liquid diode with gradient wetting channels reaches 0.56 g·h⁻¹, effectively dehumidifying and dissipating body heat with a temperature reduction of 6.3 °C. The devices deliver a DC current output of 0.40 mA·cm⁻²—twice that of devices without the liquid diode—sufficient to power a wide range of practical wearable electronics.

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Introduction

The growing demands for green and wearable power supply have been a major global concern as a wide variety of electronic devices are emerging for “Internet of Things” (IoTs), such as human activity monitoring and human-machine interaction^1,2,3,4. The power supply devices are the key components in the electronic systems that guarantee the stable operation of integrated units. Extensive efforts have been devoted to the energy harvesting technologies (e.g., solar cells, piezoelectric generators, thermoelectric generators) for power supply, which achieve electricity generation by exposing generators to the energy sources of light, motion and temperature gradient^5,6,7. The operation of energy harvesting is highly dependent on the working environment and is insufficient to support real-time and continuous monitoring in the varied environments. Besides, the wear comfort, especially regulating moisture/sweat and body heat, is critical in the long-term wearability of wearable electronic textiles^8,9. The reported power supply devices covering the fabric or human skin inhibit the release of moisture/sweat and body heat into environment^10,11,12,13. Thus, the wearable power supplies exhibit unsatisfactory electric outputs and wearability, impeding their practical applications and mass production.

One promising approach to maintaining wearable and continuous power supplies is collecting abundant moisture and converting chemical potential energy from moisture into electricity^14,15,16,17. The sustainable electric outputs have been demonstrated with hygroelectric generators as the moisture is a ubiquitous energy source in the various environments^18,19,20. By absorbing moisture with hydrophilic layers and forming asymmetrical water and ion gradient, the hygroelectric generators achieve continuous ion migration and charge separation. However, the reported electric outputs (several microamperes) of hygroelectric generators are insufficient to power practical application^21,22. Although the high moisture absorption of hydrophilic layer is often considered, the moisture was absorbed and confined inside hydrophilic layer^23,24, the waterproof substrates on the fabrics also blocked water transport^12,25,26. Thus, the poor water regulation of hygroelectric generators without moisture and thermal management is detrimental to users’ wear comfort (Fig. 1a).

**Fig. 1: Concept and advantage of the SSF.**

Here, we propose a rationally designed self-powered and self-cooling fabric (SSF), which not only ensures a comfortable experience through effective drying and cooling, but also delivers enhanced hygroelectric power supply (Fig. 1b). The liquid diode in the SSF spontaneously pumps sweat from skin surface to the external side of the fabric and blocks environmental water infiltration, contributing to a fast water transport rate of 0.012 cm·s^-1 for dehumidification and excellent wear comfort. The water evaporation on the nylon fabrics improves by two times (from 0.28 g·h^-1 to 0.56 g·h^-1) and dissipates body heat with a skin temperature reduction of 6.3 °C for self-cooling. Besides, the devices with grid-sandwiched structures are designed and printed on the liquid diode to allow fast and directional water evaporation through the generator, which triggers fast ion migration for the enhanced charge separation and electricity generation (0.40 mA·cm^-2). The efficient moisture management and enhanced electric outputs of SSF improve human comfort and solve a series of critical challenges of wearable power supply.

Results

Designs for self-cooling and electricity generation

We developed SSF by printing hygroelectric generators (aluminium, polyvinyl alcohol/lithium chloride and graphene as bottom electrode, functional layer and top electrode, respectively) with grid-sandwiched structures (Supplementary Fig. 1) on the liquid diode for self-cooling and electricity generation (Fig. 1c). In the grid structure, the printed areas and unprinted areas are mainly responsible for electricity generation and moisture/thermal management, respectively. The liquid diode of gradient fabric (G-fabric) can transport sweat on the skin surface to external environment directionally for dehumidification and wear comfort. The water evaporation on the large surfaces of G-fabric dissipates body heat for self-cooling. The water transport also drives directional ion migration inside functional layer of hygroelectric generators for electricity generation. Moreover, SSF shows excellent comprehensive performance as wearable power supply in terms of breakthrough pressure (BP) ratio, electric outputs, temperature reduction (|ΔT |) and stretch cycles, compared with other reported generators based on water evaporation (Fig. 1d and table S1).

The nylon fabrics are endowed with gradient wetting channels by hydrophobic titanium dioxide (TiO₂) nanoparticles with gradient distribution along the water flow channels (Fig. 1e), which are achieved by spraying TiO₂ nanoparticles on the one side of fabric (Supplementary Fig. 1). The amount of TiO₂ nanoparticles decreased from the bottom to the top side to guarantee the one-way water movement in the channels with varied width. The morphology of nylon fibers and element distribution (Fig. 1f, Supplementary Fig. 2) confirm the exist of the hollow channel among nylon fibers and the vertical gradient distribution of TiO₂ nanoparticles. The Ti element of pristine nylon, hydrophilic side (“I”), hydrophobic side (“O”) is 0.0%, 10.4% and 20.5%, respectively (table S2).

The improved electricity generation is attributed to the enhanced ion migration induced by fast water evaporation in the hydrophilic layer. The hydrophilic layer is consisted of polyvinyl alcohol (PVA) chains as skeleton and lithium/chloride (Li⁺/Cl^-) ions as charge carriers. The water (H₂O) molecules are bonded to Li⁺/Cl^- ions and carry ions with different migration rates for charge separation (Fig. 1g). A 2.5 × 2.5 cm² gradient fabric dropped with 0.2 g water exhibits an evaporation rate of 1.4 kg·m^-2·h^-1 and a maximum temperature reduction of 6.3 °C (Fig. 1h), almost two times performance of fabric without modification. The SSF delivers an open-circuit voltage of 0.86 V and a short-circuit current of 0.40 mA·cm^-2 (Fig. 1i). The electric power and cooling capacity are 0.42 J and 7.6 J, respectively, in each evaporation cycle (Supplementary Note 1).

Moisture and thermal management

The directional water transport is critical to regulate wear comfort of wearable electronics by moisture/thermal managemen^27,28. The underlying principles of directional water transport in the varied channels and hydrophilicity are illustrated in the different configurations (Fig. 2a). The water in the hydrophilic channels tends to wet on the large surfaces of fabric in the evaporation, while the water in the hydrophobic channels moves towards the narrow channels by the capillary pressure. By constructing gradient wetting channels in the liquid diode, water transports from hydrophobic side (“O”) to hydrophilic side (“I”) in a one-way direction. Thus, the liquid water is pumped from skin and expelled to the external environment by evaporation. The water contact angles (Supplementary Note 2 and Supplementary Fig. 3) increase with the amount of TiO₂ nanoparticles for a higher breakthrough pressure (BP). The fabrics modified with 0.94–3.58 wt.% (“direction range”) TiO₂ are capable of blocking water by top side and transporting water from bottom side when 0.5 cm H₂O of BP is set as a boundary between “Block” and “Pass” zones (Fig. 2b and Supplementary Fig. 4). Thus, a liquid diode is achieved by conducting water flow in one direction, with low flow resistance (low BP) in the “Ⅰ” direction and high flow resistance (high BP) in the “Ⅱ” direction (Supplementary Fig. 5). Otherwise, the water wets all fabric surfaces (<0.94 wt.% TiO₂) or is locked inside flow channels (>3.58 wt.% TiO₂). The TiO₂ content on different sides follows: “O” > “I” > pristine nylon according to the intensity of Ti peak (Fig. 2c).

**Fig. 2: Liquid diode with directional water transport for dehumidification and self-cooling.**

The liquid diode is demonstrated by the water transport rate along thickness (V_T) and different water height (H_T) applied on the fabric surface (Fig. 2d). The liquid diode shows a higher V_T when water is applied on the “O” side (positive direction), while blocks water with a threshold of ~5 cm when water is applied on the “I” side (negative direction). The water droplet dyed with methylene blue wets immediately on the “I” side (Fig. 2e and Supplementary Movie 1) and spreads to the larger surface areas, with no water observed on the “O” side. Thus, the external water is prohibited from wetting on the “O” side or skin surface and evaporates into the environment from “I” side. Meanwhile, water dropped on the “O” side penetrates the fabric and spreads on the “I” side within a larger area for dehumidification (Fig. 2f and Supplementary Movie 2), leaving a dry surface of “O” side for the dehumidification and wear comfort.

According to Gibbs pinning criterion²⁹, the expansion/contraction angle (α) of flow channels and water contact angle (θ) guarantee the advancement of water flow when α + θ < 90°, which is satisfied in the “Pass” zones and unsatisfied in the “Block” zone (Supplementary Note 3 and Supplementary Fig. 5). The water evaporation rate (Fig. 2g) of gradient fabric is 0.56 g·h^-1, twice that of pristine fabric (0.28 g·h^-1). The faster water evaporation (Supplementary Note 4 and Supplementary Fig. 6) as well as satisfactory air/moisture permeability (Supplementary Fig. 7) are also demonstrated by the SSF devices. The significantly improved drying rate by the gradient fabric is attributed to the directional water transport toward “I” side and the wetting on a larger surface area. The wetting area of “O” side and “I” side (Fig. 2h) is 0.8 cm² and 7.0 cm², respectively, indicating that the evaporation area is increased by more than 8 times after water passes through the gradient fabric (“O” to “I”). The V_T from “O” side to “I” side is 0.012 cm·s^-1 for dehumidification, while the horizontal water transport rate on the “I” side is 0.05 cm·s^-1 for wetting and water evaporation. The skin surface covered with gradient fabric is dry after 1 min operation and exhibits a better dehumidification performance, compared with wet skin without gradient fabric (Fig. 2i). The surface temperature of sweating arms is reduced from 33.1 °C to 26.8 °C after operation in room conditions without convection (Fig. 2j and Supplementary Fig. 8).

Electricity generation with high electric outputs

In addition to wear comfort, the directional water transport facilitates energy harvesting by the synergistic effect of water transport and ion migration in the functional layer (Fig. 3a). Once the functional layer absorbs liquid water, water molecules transport from bottom side to top side under water gradient and drive ion migration by forming hydrated ion cluster³⁰. The intensity difference of ν(‒OH) at ~3300 cm^-1 on the top and bottom surface of functional layer (Supplementary Fig. 9a) indicates that vertical water gradient exists during operation. The water gradient and ion migration vanish after water is fully evaporated on the top side to achieve a full operation cycle. The SSF exposed to symmetrical relative humidity (RH) and asymmetrical RH show no current output and 0.15 mA·cm^-2, respectively (Supplementary Note 5 and Supplementary Fig. 10). Thus, the water transport with hydrated ion clusters contributes to the formation of internal electric field (Supplementary Fig. 11).

**Fig. 3: Electricity generation of SSF.**

The current output is significantly improved from 0.19 mA·cm^-2 to 0.40 mA·cm^-2 by designing internal directional water transport (Fig. 3b, Supplementary Fig. 12 and Supplementary Movie 3). The SSF device with gradient nylon also delivers a faster current response due to the fast vertical water transport. The devices without fabrics show a transient current peak of 0.15 mA·cm^-2 after absorbing water owing to the rapid vanish of water gradient (Supplementary Fig. 13). Thus, the design of directional water transport not only improves wear comfort of hygroelectric generator but also enhances ion migration for higher electric outputs. The SSF achieves continuous electric outputs with stable long-term evaporation (Supplementary Fig. 14) by fixing the bottom side of SSF on the water surface over a week (Fig. 3c). Besides, the graphene as top electrode was proved to facilitate water evaporation³¹ for higher electric outputs, while aluminium (Al) as bottom electrode could also improve electric outputs by the higher electric conductivity (Supplementary Note 6, Supplementary Fig. 15 and 16). No chemical reaction between electrode and functional layer is detected according to the cyclic voltammetry curve and element distribution in Supplementary Fig. 17.

The interaction between charge carriers and functional layer is closely related to the electricity generation. The SSF delivers no electric output without lithium chloride (LiCl), owing to no charge carrier available. By increasing the ratio of LiCl and PVA in the functional layer, the electric outputs of devices improve (Fig. 3d). With the addition of LiCl, the ratio of intermediate water increases (Supplementary Note 7 and Supplementary Fig. 18), which can be vaporized with less energy and a higher evaporation rate, compared with free water in the functional layer³². Besides, the increased contents of LiCl endow the functional layers with more charge carriers and lower ionic resistance (Fig. 3e) in the electrochemical impedance spectroscopy (EIS). Moreover, the added LiCl salts in the PVA chains contribute to a higher electrostatic gradient along the PVA chains for charge separation (Supplementary Note 8 and Supplementary Fig. 19). The wider electrostatic potential (ESP) distribution of PVA/LiCl indicates high water absorption ability according to the density functional theory (DFT) calculation. An ultrahigh output of 0.48 mA·cm^-2 in the sweat evaporation was achieved (Fig. 3f), which is higher than the output (0.40 mA·cm^-2) with D.I. water as salts provide more carriers (Supplementary Note 9 and Supplementary Fig. 20) for electricity generation. Unlike the common reported hygroelectric generators with several microamperes¹⁵, the significantly enhanced current output (hundreds of microamperes) with liquid water in this work is more promising as practical power supply.

Various models were carried out to reveal the mechanism of electricity generation with water transport and ion migration. Once SSF absorbs water from bottom side, the top surface potential of hydrophilic layer becomes more negative with the extended operation time according to the Kelvin probe force microscopy (KPFM) (Fig. 3g), which demonstrates that more Cl^- ions are accumulated on the top side by the water transport. The water molecules with a higher polarity are also demonstrated to be the better carriers of ion migration for electricity generation (Supplementary Fig. 21). The faster ion migration of Cl^- ions than that of Li⁺ ions constructs a negative charge surface on the top side and a positive charge surface on the bottom side along the direction of water transport.

The detailed 3D snapshot of functional layer was performed in the molecular dynamics (MD) simulation by stacking two gel layers together, which starts with the top layer (LiCl:H₂O:PVA = 100:1200:70) and the bottom layer (LiCl:H₂O:70 = 100:6000:70) at t = 0 ns (Fig. 3h, Supplementary Note 10 and Supplementary Fig. 22). The water transport and ion migration from bottom layer to top layer under water gradient were observed (t = 10 ns) in the same polarity with electric outputs of SSF (Fig. 3h). The diffusion coefficient of Li⁺ and Cl^- from mean squared displacement (MSD) calculation is 0.38×10^-5cm²·s^-1 and 2.54×10^-5cm²·s^-1, respectively, indicating that Cl^- ions can be separated from Li⁺ ions by water transport (Fig. 3i).

From DFT calculation, the energy barrier of Li⁺ and Cl^- migration along PVA chain is 0.40 eV and 0.18 eV (Supplementary Fig. 23), respectively, as Li⁺ ions shows a higher binding energy with PVA/H₂O in the functional layer (Supplementary Fig. 24). Thus, polymer chains can work as ion migration paths for charge separation of Li⁺ and Cl^- ions (Fig. 3j) for electricity generation. Radial distribution function (RDF) and coordination number (CN) of Li⁺ ions dispersed in the functional layer are lower than that of Li⁺ ions dispersed in the pure water (Supplementary Fig. 25), which also demonstrates that polymer chains occupy inner solvent sheath of hydrated Li⁺ ions and provide transportation paths for Li⁺ ions. The current outputs of devices fabricated with other salts (e.g., NaCl) are lower (0.3 mA·cm^-2 in Supplementary Fig. 26a) and can be attributed to the lower electric conductivity by a lower ion migration rate (Supplementary Fig. 26b). Li⁺ ions show a higher electrostatic force with water to form more hydrated ions for a faster ion migration rate (Supplementary Fig. 27).

Simultaneous self-cooling and electricity generation

The self-cooing and electricity generation are evaluated simultaneously to achieve excellent comprehensive performance. The higher porosity of grid-structure device represents a higher ratio of unprinted area on the liquid diode, which leads to the overall faster water evaporation rate and lower temperature (Fig. 4a). The faster water evaporation also facilitates ion migration for higher electric outputs. However, the higher porosity represents a smaller printed area for current collection²⁸. Therefore, the current output and released charges of SSF increase and then decrease with the increasing porosity (Fig. 4b and Supplementary Fig. 28). The smaller pore size, instead of pore shape, contributes to more uniform water evaporation and higher electric outputs (Supplementary Fig. 29). Besides, the SSF shows similar thermal resistance (2–3 m²·K·W^-1) with different porosity and gel thickness in the equivalent thermal resistance network (Supplementary Note 11 and Supplementary Fig. 30). The printed layers are relatively thin in thickness (0.17 mm) compared with fabrics (0.5 mm), which leads to no obvious increased thermal resistance after printing various layers. By dropping water in the different spots of bottom side, the performance of devices shows no significant variation in the various spots (Fig. 4c) owing to the high wetting areas of gradient fabric (Fig. 2g). The faster water evaporation in the thinner fabrics and functional layers enhances electric outputs of SSF (Supplementary Fig. 31).

**Fig. 4: Thermal and electrical performance of SSF.**

The strategy of simultaneous self-cooling and electricity generation is also applicable to other commonly used fabrics (Fig. 4d). The nylon fabrics show a lower moisture regain and a higher water evaporation rate³³, which are better than wool, silk and cotton in terms of electric outputs and cooling performance. The electric output and cooling performance also improve with more water dropped onto the bottom side (Fig. 4e). No further improvement is observed with excess water content (>0.03 g·cm^-2) as excess water covers the whole device without water gradient. The devices can operate in a wide range of temperatures and deliver increased electric outputs in the higher operation temperatures (Fig. 4f) and greater convective conditions (Supplementary Fig. 32) due to faster water evaporation and ion migration. Besides, the faster evaporation in the lower RH and the greater water absorption in the higher RH are beneficial to achieving high current outputs. Thus, the SSF exhibits better overall performance compared with other generators (table S3).

The stable mechanical performance is demonstrated with repeated stretch cycles, where no obvious performance decline occurs after printing (Supplementary Fig. 33) and 10000 tensile cycles (Fig. 4g). Stable electric outputs are achieved in the various mechanical tests with 0–50% strain, 0‒150° bending angle and 10000 bending cycles (Supplementary Fig. 34). The devices also exhibit stable operation cycles for long-term application (Fig. 4h). In an operation cycle, the electric outputs start with dropping water and last until devices are fully dried. The SSF devices achieve a linear increase of accumulated released charges in the repeated operation cycles (1.36 C charge per cycle). No chemical leakage (Supplementary Fig. 35 and 36) or electric performance decline (Supplementary Fig. 37) occurs in the operation cycles or long-term storage period. The SSF achieves a maximum output of 77.5 µW with 0.42 J when the resistance of the external load is 2 kΩ (Fig. 4i). Moreover, the integrated device units deliver linearly increased electric outputs by printing multiple units in series or parallel (17.16 V and 7.90 mA with 20 device units in Supplementary Fig. 38).

Practical wearable application demonstrations

Our devices can be integrated into the wearable electronic system for practical application. The devices were printed onto different types of clothes (Fig. 5a), which demonstrates that SSF is applicable to various fabrics and body parts for a wide range of practical application. The device was printed with a large-scale area (14.5×14.5 cm²) on the clothes and shows a uniform temperature reduction of 6.3 °C on the large-scale area with sweat (Fig. 5b and Supplementary Fig. 39). The skin temperature drops from 33.1 °C to 26.8 °C in 16 mins (Fig. 5c) to achieve a quick wear comfort. Two device units were printed in series and powered a flexible LED strip directly for a wearable LED display with various letters (Fig. 5d).

**Fig. 5: Application demonstration of wearable electronic systems.**

The wearable monitoring system is critical for the health care of infants or disable people with insufficient communication ability³⁴. Owing to the specific relation between water content and current outputs in this work, the SSF integrated with diaper delivers immediate information of the leaked urine content by generating corresponding current output (Fig. 5e). The wireless monitoring system consists of SSF, diaper, wireless current sensor and monitor (Fig. 5f and Supplementary Movie 4). The urgency level of help in need is described as “Comfort”, “Low”, “Moderate”, “High”, “Immediate” according to maximum current output in the range of 0‒0.1, 0.1‒0.2, 0.2‒0.3, 0.3‒0.4, >0.4, respectively (Fig. 5g). Besides, the harvested energy by SSF can be stored in the various power storage devices (Supplementary Fig. 40) as power supply. The wireless detection of body signals is also demonstrated with a battery charged by SSF, wireless sensor and monitor (Fig. 5h and Supplementary Fig. 41) to transmit immediate signals of skin temperature and heart rate (Figs. 5i and 5j) by controlling switch 1# and switch 2# (S1 and S2).

Discussion

We have developed a self-cooling and self-powered fabric that achieves moisture/thermal management and enhanced electricity generation by synergistic directional water transport and ion migration. The gradient wetting channels in the liquid diode are designed to absorb water from skin surface and block external water by directional water transport. The asymmetrical water evaporation on a large area contributes to a fast water evaporation rate of 0.56 g·h^-1 and a considerable temperature reduction of 6.3 °C for wear comfort. The different ion migration rates of Li⁺/Cl^- ions in the directional water transport boost charge separation for the enhanced electric output of 0.40 mA·cm^-2. The temperature drops and electric outputs are also balanced to deliver excellent comprehensive performance by rationally designing grid-sandwiched SSF. Meanwhile, the device exhibits satisfactory operation stability and is integrated with multiple practical electronic devices to provide health care and monitor human activity. Our design proposes an effective approach that not only ensures excellent wearability but also has a great potential for energy harvesting and power supply, which will be quite promising for practical application once the washable design and power management system are integrated with SSF in the future.

Methods

Liquid diode preparation

The plain knitted nylon fabrics with 83% Tactel and 17% Lycra (Sunikorn Knitters Limited, Hong Kong) were used as substrates of liquid diode for good elasticity and low hysteresis. The nylon fabrics were designed with a yarn density of 43 courses·m^-1 and 22 wales·m^-1. The weight of the nylon fabric is 195 g·m^-2, the linear density of the Tactel yarn and Lycra yarn is 702 denier/68 filaments and 40 denier/5 filaments, respectively, fiber diameter is 12–24 µm. The nylon fabrics were cleaned with improved hydrophilicity by the plasma (Plasma Etch PE-25) with O₂ for 10 min before their use. The fabrics with wetting channels were fabricated by spraying hydrophobic particles on the bottom side of fabrics. To fabricate sprayable dispersion with hydrophobic nanoparticles, the mixture of 1H,1H,2H,2H-Perfluorooctyltriethoxysilane (98%, Sigma), TiO₂ (particle size <100 nm, Sigma), and ethanol (>95%, Sigma) were mixed at a mass ratio of 1:5:200 and were stirred for 5 h before spraying. The dispersion was uniformly sprayed onto the bottom side of the fabrics with a constant distance. Then, the fabrics were dried at 50 °C for 10 min before testing and printing.

Device preparation

The graphene pastes (<15 Ω·cm^-1) and Al powders (>95%, <15 µm) were mixed at a mass ratio of 5:1 by stirring for 2 h. The mixed pastes were printed onto the top side of fabrics by screen printing and were dried at 50 °C for 10 min to work as bottom electrodes. The printable gels were fabricated by heating and stirring PVA (Mw~61000, Sigma) in the LiCl (>99%, Sigma) solution at 90 °C for 2 h (mass ratio of LiCl:PVA:H₂O = 1:2.5:17). Then, the gels were printed onto the bottom electrode by screen printing and were dried at 50 °C in the vacuum oven for 2 h. The graphene pastes were printed onto the gels, followed by drying at 50 °C for 10 min.

Thermal measurement

Thermal images and videos were collected by the thermal imaging camera (Fluke Ti400U Thermal Imager, precision: ± 2 °C or 2%) at room temperature of 25 °C and 55% RH. The temperature was recorded by K-type thermocouples and Anbat AT4516 (Applent Instruments Ltd.) on the bottom side of SSF. The temperature of SSF or human skin on the forearm was collected after it reaches the minimum value. The distilled water was stored at same temperature as the forearm surface. 0.2 g distilled water was sprayed onto the forearm to mimic sweat evaporation before the operation of SSF. The artificial sweat (pH=4.7) was prepared with 2 wt.% NaCl, 1.8 wt.% NH₄OH, 0.5 wt.% acetic acid, and 1.5 wt.% actic acid, according to International Organization for Standardization (ISO) 3160-2.

Electrical measurement

The relative humidity of electrical measurement was adjusted in an environmental chamber. The electric outputs of self-powered and self-cooling fabric (SSF) were collected by Keithley 2400 (Tektronix, USA). The surface potentials of device surface were recorded by Kelvin probe force microscopy (KPFM) with Bruker Dimension Icon machine. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry curve were performed by Autolab PGSTAT302N platform with two-electrode test at room humidity (RH = 55%). The tensile test was performed by Instron 5544 in extension mode with a speed of 10 mm min^-1.

Characterizations

The morphology and element distribution of devices were characterized by the field-emission scanning electron microscope (FE-SEM, Tescan MAIA3) equipped with an energy dispersive spectroscopy (EDS). The elements in the different sides of fabrics were characterized by X-ray photoelectron spectroscopy (XPS) with the Al-Kα radiation (8.34 Å) as a power source in the ESCALAB 250Xi (Thermo Fisher) spectrometer. Fourier-transform infrared spectroscopy (FTIR, PerkinElmer, Spectrum 100) was used to record wetting strates of different surfaces. The breakthrough pressure of water flow through fabrics from was recorded by home-made platform in Supplementary Fig. 4. The wetting area of saline droplet with 0.9 wt.% NaCl on the fabric was obtained by moisture management tester (MMT, SDL ATLAS Ltd., China). The planar wetting area with time was used to calculate planar water transport rates. The water contact angle was measured by a drop shape analyzer (Krüss, Hamburg, Germany). to calculate vertical water transport rates. The permeability tests were performed by using a MO21S permeability tester (SDL Americ, Inc.). The water states of intermediate water (IW) and free water (FW) in the functional layer were revealed with Raman spectrometer (Renishaw inVia Reflex) at the wavelength of 532 nm.

Data availability

The data supporting the findings of this study are included in the main text and supplementary information files. Raw data can be obtained from the corresponding author upon request. Source data are provided with this paper.

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Acknowledgements

X.T. acknowledges the support by Innovation and Technology Commission of Hong Kong SAR Government (No. MRP/020/21), Hong Kong Research Grants Council (Nos. 15302121 and 15201922) and Hong Kong Polytechnic University (No. 847 A and P0036628-49621).

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Authors and Affiliations

Research Institute for Intelligent Wearable Systems, The Hong Kong Polytechnic University, Hong Kong, China
Renbo Zhu, Zhongliang Zhang, Yonghui Luo, Jing Yang, Su Liu & Xiaoming Tao
School of Fashion and Textiles, The Hong Kong Polytechnic University, Hong Kong, China
Renbo Zhu, Zhongliang Zhang, Yonghui Luo, Jing Yang, Su Liu & Xiaoming Tao
Department of Applied Biology and Chemical Technology, Faculty of Science, The Hong Kong Polytechnic University, Hong Kong, China
Yufei Zhang
South China Advanced Institute for Soft Matter Science and Technology, School of Emergent Soft Matter, Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou, China
LinGe Wang

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Renbo Zhu
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Zhongliang Zhang
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Yonghui Luo
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Jing Yang
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Su Liu
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Yufei Zhang
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LinGe Wang
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Xiaoming Tao
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Contributions

X.T. and R.Z. conceived the idea. R.Z. carried out sample preparation, characterizations, testing and writing. Z.Z. designed the integrated electronic systems for application. Y.L., Y.Z. and L.W. modified parameters in the sample preparation and helped with SEM characterization. J.Y. performed the calculations in this work. S.L. helped with indoor and outdoor experiments. All authors discussed the results and reviewed the manuscript.

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Correspondence to Xiaoming Tao.

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Zhu, R., Zhang, Z., Luo, Y. et al. Sweat-pumping cooling fabric for enhanced power generation and comfort. Nat Commun 17, 4374 (2026). https://doi.org/10.1038/s41467-026-70856-8

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Received: 22 July 2025
Accepted: 04 March 2026
Published: 24 March 2026
Version of record: 15 May 2026
DOI: https://doi.org/10.1038/s41467-026-70856-8