An electrocyte-inspired moisture-driven electricity generator for self-sustained water electrolysis

Abstract

Harvesting electricity from ubiquitous moisture offers the promise of clean power for self-sustained systems. Despite extensive efforts, achieving high-power electricity generation remains challenging. Existing studies mimicking electric eels’ electrogenesis to enhance their electrical performance focused on the two-membrane structure that linearly adds up the voltage, but their current output was either transient or limited to microamperes, because of the large resistance for ion diffusing across material interfaces. Here, we report an electrocyte-inspired moisture-driven electricity generator (EMEG) made from an interphase-mediated Janus film. The continuous interphase significantly alleviates the ion migration resistance, boosting the current output to 150 µA and sustaining the voltage of 0.8 V continuously for more than 1000 h. We also show that integrated EMEGs were easily assembled to self-powered smart watch for emergency rescue. Furthermore, the integrated EMEGs achieved self-sustained and moisture-powered water splitting with a steady hydrogen production. Our results provide a rational for bio-inspired designs toward green and sustained power generation.

References

[1] Liu X, Gao H, Ward JE, et al. Power generation from ambient humidity using protein nanowires. Nature. 2020; 578: 550-554.

[2] Zhang Z, Li X, Yin J, et al. Emerging hydrovoltaic technology. Nat Nanotechnol. 2018; 13: 1109-1119.

[3] Shen D, Duley WW, Peng P, et al. Moisture-enabled electricity generation: from physics and materials to self-powered applications. Adv Mater. 2020; 32:2003722.

[4] Wei Q, Ge W, Yuan Z, et al. Moisture electricity generation: mechanisms, structures, and applications. Nano Res. 2023; 16: 7496-7510.

[5] Lim H, Kim MS, Cho Y, et al. Hydrovoltaic electricity generator with hygroscopic materials: a review and new perspective. Adv Mater. 2023; 36:202301080.

[6] Zhao F, Cheng H, Zhang Z, Jiang L, Qu L. Direct power generation from a graphene oxide film under moisture. Adv Mater. 2015; 27: 4351-4357.

[7] Huang Y, Zhou K, Cheng H, et al. Three-dimensional printing of high-performance moisture power generators. Adv Funct Mater. 2023; 34:2308620.

[8] Ren G, Wang Z, Zhang B, et al. A facile and sustainable hygroelectric generator using whole-cell geobacter sulfurreducens. Nano Energy. 2021; 89:106361.

[9] Li M, Zong L, Yang W, et al. Biological nanofibrous generator for electricity harvest from moist air flow. Adv Funct Mater. 2019; 29:1901798.

[10] Lyu Q, Peng B, Xie Z, et al. Moist-induced electricity generation by electrospun cellulose acetate membranes with optimized porous structures. ACS Appl Mater Interfaces. 2020; 12: 57373-57381.

[11] Sun Z, Feng L, Xiong C, et al. Electrospun nanofiber fabric: an efficient, breathable and wearable moist-electric generator. J Mater Chem A. 2021; 9: 7085-7093.

[12] Shen D, Xiao M, Zou G, et al. Self-powered wearable electronics based on moisture enabled electricity generation. Adv Mater. 2018; 30:1705925.

[13] Liu J, Huang L, He W, et al. Moisture-enabled hydrovoltaic power generation with milk protein nanofibrils. Nano Energy. 2022; 102:107709.

[14] Xu T, Ding X, Huang Y, et al. An efficient polymer moist-electric generator. Energy Environ Sci. 2019; 12: 972-978.

[15] Chen N, Liu Q, Liu C, et al. Meg actualized by high-valent metal carrier transport. Nano Energy. 2019; 65:104047.

[16] Zhao Q, Jiang Y, Duan Z, et al. A Nb₂CT_x/sodium alginate-based composite film with neuron-like network for self-powered humidity sensing. Chem Eng J. 2022; 438:135588.

[17] Huang Y, Cheng H, Yang C, et al. All-region-applicable, continuous power supply of graphene oxide composite. Energy Environ Sci. 2019; 12: 1848-1856.

[18] Huang Y, Cheng H, Yang C, et al. Interface-mediated hygroelectric generator with an output voltage approaching 1.5 volts. Nat Commun. 2018; 9: 4166.

[19] He T, Wang H, Lu B, et al. Fully printed planar moisture-enabled electric generator arrays for scalable function integration. Joule. 2023; 7: 935-951.

[20] Sun Z, Wen X, Wang L, Yu J, Qin X. Capacitor-inspired high-performance and durable moist-electric generator. Energy Environ Sci. 2022; 15: 4584-4591.

[21] Cheng H, Huang Y, Zhao F, et al. Spontaneous power source in ambient air of a well-directionally reduced graphene oxide bulk. Energy Environ Sci. 2018; 11: 2839-2845.

[22] Chen S, Xia H, Ni QQ. A wearable sustainable moisture-induced electricity generator based on rGO/GO/rGO sandwich-like structural film. Adv Electron Mater. 2021; 7:2100222.

[23] Chen F, Zhang S, Guan P, et al. High-performance flexible graphene oxide-based moisture-enabled nanogenerator via multilayer heterojunction engineering and power management system. Small. 2023; 20:2304572.

[24] Zhao K, Lee JW, Yu ZG, et al. Humidity-tolerant moisture-driven energy generator with MXene aerogel–organohydrogel bilayer. ACS Nano. 2023; 17: 5472-5485.

[25] Li P, Hu Y, He W, et al. Multistage coupling water-enabled electric generator with customizable energy output. Nat Commun. 2023; 14: 5702.

[26] Guo C, Tang H, Wang P, et al. Radiative cooling assisted self-sustaining and highly efficient moisture energy harvesting. Nat Commun. 2024; 15: 6100.

[27] Zhao F, Liang Y, Cheng H, Jiang L, Qu L. Highly efficient moisture-enabled electricity generation from graphene oxide frameworks. Energy Environ Sci. 2016; 9: 912-916.

[28] Lee S, Eun J, Jeon S. Facile fabrication of a highly efficient moisture-driven power generator using laser-induced graphitization under ambient conditions. Nano Energy. 2020; 68:104364.

[29] Yang S, Tao X, Chen W, et al. Ionic hydrogel for efficient and scalable moisture-electric generation. Adv Mater. 2022; 34:2200693.

[30] Zhang H, He N, Wang B, et al. High-performance, highly stretchable, flexible moist-electric generators via molecular engineering of hydrogels. Adv Mater. 2023; 35:2300398.

[31] Liu H, Liu L, Du Y, et al. Self-sustained water and electricity generation from ambient humidity by using metal-ion controlled hygroscopic hydrogels. Adv Funct Mater. 2025;2420936.

[32] Li L, Dong F, Miao P, et al. High-efficiency moisture energy harvesting at −30°C via hybrid solute engineering. Energy Environ Sci. 2025; 18: 2985-2994.

[33] Yang S, Zhang L, Mao J, et al. Green moisture-electric generator based on supramolecular hydrogel with tens of milliamp electricity toward practical applications. Nat Commun. 2024; 15: 3329.

[34] Schroeder TBH, Guha A, Lamoureux A, et al. An electric-eel-inspired soft power source from stacked hydrogels. Nature. 2017; 552: 214-218.

[35] Gotter AL, Kaetzel MA, Dedman JR. Electrophorus electricus as a model system for the study of membrane excitability. Comp Biochem Physiol A: Mol Integr Physiol. 1998; 119: 225-241.

[36] Hong S-I. Electric eel electricity. Phys Educ. 2020; 55:053001.

[37] Zhang Y, Riexinger J, Yang X, et al. A microscale soft ionic power source modulates neuronal network activity. Nature. 2023; 620: 1001-1006.

[38] Wang H, Sun Y, He T, et al. Bilayer of polyelectrolyte films for spontaneous power generation in air up to an integrated 1,000 V output. Nat Nanotechnol. 2021; 16: 811-819.

[39] Yang W, Li X, Han X, et al. Asymmetric ionic aerogel of biologic nanofibrils for harvesting electricity from moisture. Nano Energy. 2020; 71:104610.

[40] Yang W, Lv L, Li X, et al. Quaternized silk nanofibrils for electricity generation from moisture and ion rectification. ACS Nano. 2020; 14: 10600-10607.

[41] Lu W, Ding T, Wang X, et al. Anion‒cation heterostructured hydrogels for all-weather responsive electricity and water harvesting from atmospheric air. Nano Energy. 2022; 104:107892.

[42] Chen T, Huang H, Cao J, et al. Preparation and characterization of alginate/HACC/oyster shell powder biocomposite scaffolds for potential bone tissue engineering applications. RSC Adv. 2016; 6: 35577–35588.

[43] Wang H, Cheng H, Huang Y, et al. Transparent, self-healing, arbitrary tailorable moist-electric film generator. Nano Energy. 2020; 67:104238.

[44] Catania K. The shocking predatory strike of the electric eel. Science. 2014; 346: 1231-1234.

[45] Carlson BA. Animal behavior: electric eels amp up for an easy meal. Curr Biol. 2015; 25: R1070-R1072.

[46] Tan J, Fang S, Zhang Z, et al. Self-sustained electricity generator driven by the compatible integration of ambient moisture adsorption and evaporation. Nat Commun. 2022; 13: 3643.

[47] He W, Wang H, Huang Y, et al. Textile-based moisture power generator with dual asymmetric structure and high flexibility for wearable applications. Nano Energy. 2022; 95:107017.

[48] Liu J, Cai X, Wang Y, et al. Moisture-induced electrical power generation with waste activated sludge. Chem Eng J. 2023; 472:144868.

[49] Bai J, Hu Y, Guang T, et al. Vapor and heat dual-drive sustainable power for portable electronics in ambient environments. Energy Environ Sci. 2022; 15: 3086-3096.

[50] Månsson M, Sugiyama J. Muon-spin relaxation study on Li- and Na-diffusion in solids. Phys Scr. 2013; 88:068509.

[51] Zhang Z, Yang S, Zhang P, et al. Mechanically strong MXene/Kevlar nanofiber composite membranes as high-performance nanofluidic osmotic power generators. Nat Commun. 2019; 10: 2920.

[52] Wang Y, Zhang Y, Xin X, et al. In situ photocatalytically enhanced thermogalvanic cells for electricity and hydrogen production. Science. 2023; 381: 291-296.

[53] Wu X, Li J, Li Y, Wen Z. NiFeP‒MoO₂ hybrid nanorods on nickel foam as high-activity and high-stability electrode for overall water splitting. Chem Eng J. 2021; 409:128161.

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2025 The Author(s). Droplet published by Jilin University and John Wiley & Sons Australia, Ltd.