Hydroelectric-Coupled Supercapacitor System for Simultaneous Energy Conversion and Storage With Binder-Free WS₂ Nanostructures

Abstract

The growing adoption of flexible electronics, electric mobility, and decentralized energy systems has intensified the demand for scalable electrochemical energy-storage technologies capable of delivering high power under dynamic and mechanically flexible conditions, which are essential for self-sustaining energy ecosystems. In this work, binder-free tungsten disulfide (BF-WS₂) nanoarchitectured electrodes were directly grown on carbon cloth via a one-step hydrothermal process and investigated for scalable supercapacitor applications. Structural and chemical analyses confirm the formation of a hexagonal WS₂ nanostructure grown on the carbon cloth substrate. The BF-WS₂ electrode exhibits a specific capacitance of 1261 F g⁻¹ at 5 mV s⁻¹, demonstrating excellent electrochemical energy storage capability. A flexible BF-WS₂ symmetric solid-state supercapacitor (BF-WS₂ SSC) fabricated using a PVA/H₂SO₄ gel electrolyte delivers a device capacitance of 363.5 F g⁻¹ at 7.5 mA, achieving an energy density of 50 Wh kg⁻¹ and a power density of 9090.9 W kg⁻¹. Moreover, modular series-parallel integration enables tunable voltage/current output, and direct coupling with a water-flow-driven hydroelectric generator demonstrates renewable-energy-driven charging of the stacked BF-WS₂ SSC device to 5 V. This work highlights binder-free WS₂ nanostructure as a scalable electrode platform for modular, flexible, and hydroelectric-assisted self-powered supercapacitor systems.

Keywords

binder-free / electrochemical energy storage / hydroelectricity / self-powered / tungsten disulfide

References

[1] F. Jiang, X. Yuan, L. Hu, et al., “A Comprehensive Review of Energy Storage Technology Development and Application for Pure Electric Vehicles,” Journal of Energy Storage 86 (2024): 111159.

[2] M. Waseem, G. S. Lakshmi, M. Ahmad, and M. Suhaib, “Energy Storage Technology and Its Impact in Electric Vehicle: Current Progress and Future Outlook,” Next Energy 6 (2025): 100202.

[3] J. R. Miller and P. Simon, “Electrochemical Capacitors for Energy Management,” Science 321 (2008): 651–652.

[4] M. Armand and J.-M. Tarascon, “Building Better Batteries,” Nature 451 (2008): 652–657.

[5] J. B. Goodenough and K.-S. Park, “The Li-Ion Rechargeable Battery: A Perspective,” Journal of the American Chemical Society 135 (2013): 1167–1176.

[6] A. Manthiram, “A Reflection on Lithium-Ion Battery Cathode Chemistry,” Nature Communications 11 (2020): 1550.

[7] X. Pu, W. Hu, and Z. L. Wang, “Toward Wearable Self-Charging Power Systems: The Integration of Energy-Harvesting and Storage Devices,” Small 14 (2018): 1702817.

[8] Z. L. Wang, “Triboelectric Nanogenerators as New Energy Technology for Self-Powered Systems and as Active Mechanical and Chemical Sensors,” ACS Nano 7 (2013): 9533–9557.

[9] Z. L. Wang, “Self-Powered Nanosensors and Nanosystems,” Advanced Materials 24 (2012): 280–285.

[10] B. Dunn, H. Kamath, and J.-M. Tarascon, “Electrical Energy Storage for the Grid: A Battery of Choices,” Science 334 (2011): 928–935.

[11] P. Simon and Y. Gogotsi, “Materials for Electrochemical Capacitors,” Nature Materials 7 (2008): 845–854.

[12] N. A. Salleh, S. Kheawhom, N. Ashrina A Hamid, W. Rahiman, and A. A. Mohamad, “Electrode Polymer Binders for Supercapacitor Applications: A Review,” Journal of Materials Research and Technology 23 (2023): 3470–3491.

[13] N. A. Wadodkar, R. S. Salunke, S. K. Pawar, et al., “Next-Generation Supercapacitors: Advances in Binder-Free Electrodes, Scalable Fabrication, and Emerging Applications,” Advanced Sustainable Systems 10 (2026): e00599.

[14] J. Heumann, D. Müller, N. T. M. Baltes, et al., “Additively Manufactured Binder-Free Electrodes for Supercapacitors,” Batteries & Supercaps 8 (2025): 2400455.

[15] M. Chhowalla, H. S. Shin, G. Eda, L.-J. Li, K. P. Loh, and H. Zhang, “The Chemistry of Two-Dimensional Layered Transition Metal Dichalcogenide Nanosheets,” Nature Chemistry 5 (2013): 263–275.

[16] X. Duan and H. Zhang, “Introduction: Two-Dimensional Layered Transition Metal Dichalcogenides,” Chemical Reviews 124 (2024): 10619–10622.

[17] L. Li, J. Gao, V. Cecen, et al., “Hierarchical WS₂@NiCo₂O₄ Core–Shell Heterostructure Arrays Supported on Carbon Cloth as High-Performance Electrodes for Symmetric Flexible Supercapacitors,” ACS Omega 5 (2020): 4657–4667.

[18] R. Somveer, J. Yadav, R. Pani, et al., “Hydrothermally Synthesized 2H-WS₂ Nanorods for Improved Supercapacitor Electrode Performance,” Physical Chemistry Chemical Physics: PCCP 27 (2025): 12231–12239.

[19] S. Liu, Y. Zeng, M. Zhang, et al., “Binder-Free WS₂ Nanosheets With Enhanced Crystallinity as a Stable Negative Electrode for Flexible Asymmetric Supercapacitors,” Journal of Materials Chemistry A 5 (2017): 21460–21466.

[20] U. Perişanoğlu, E. Kavaz Perişanoğlu, Z. Kudaş, D. Ekinci, I. Ismail, and E. Gür, “Advanced Flexible Supercapacitors: Vertical 2D MoS₂ and WS₂ Nanowalls on Graphenated Carbon Nanotube Cotton,” Nanoscale 17 (2025): 6704–6717.

[21] G. A. Parks, “The Isoelectric Points of Solid Oxides, Solid Hydroxides, and Aqueous Hydroxo Complex Systems,” Chemical Reviews 65 (1965): 177–198.

[22] Y. Shang, J. Xia, Z. Xu, and W. Chen, “Hydrothermal Synthesis and Characterization of Quasi-1-D Tungsten Disulfide Nanocrystal,” Journal of Dispersion Science and Technology 26 (2005): 635–639.

[23] A. K. Nayak, S. Lee, Y. I. Choi, H. J. Yoon, Y. Sohn, and D. Pradhan, “Crystal Phase and Size-Controlled Synthesis of Tungsten Trioxide Hydrate Nanoplates at Room Temperature: Enhanced Cr(VI) Photoreduction and Methylene Blue Adsorption Properties,” ACS Sustainable Chemistry & Engineering 5 (2017): 2741–2750.

[24] S. Duraisamy, A. Ganguly, P. K. Sharma, J. Benson, J. Davis, and P. Papakonstantinou, “One-Step Hydrothermal Synthesis of Phase-Engineered MoS₂/MoO₃ Electrocatalysts for Hydrogen Evolution Reaction,” ACS Applied Nano Materials 4 (2021): 2642–2656.

[25] J. N. Coleman, M. Lotya, A. O'Neill, et al., “Two-Dimensional Nanosheets Produced by Liquid Exfoliation of Layered Materials,” Science 331 (2011): 568–571.

[26] R. Swaminathan, P. Pazhamalai, V. Mohan, K. Krishnamoorthy, and S.-J. Kim, “Topochemically Prepared Tungsten Disulfide Nanostructures as a Novel Pseudocapacitive Electrode for High Performance Supercapacitor,” Journal of Colloid and Interface Science 652 (2023): 845–855.

[27] Q. H. Wang, K. Kalantar-Zadeh, A. Kis, J. N. Coleman, and M. S. Strano, “Electronics and Optoelectronics of Two-Dimensional Transition Metal Dichalcogenides,” Nature Nanotechnology 7 (2012): 699–712.

[28] H. R. Gutiérrez, N. Perea-López, A. L. Elías, et al., “Extraordinary Room-Temperature Photoluminescence in Triangular WS₂ Monolayers,” Nano Letters 13 (2013): 3447–3454.

[29] S. Jian, W. Wang, L. Wu, et al., “Construction of Highly Efficient Carbon Cloth-Supported S-Scheme Co₃O₄/AgIO₄ Heterojunction for Photocatalytic Degradation of Rhodamine B Organic Dye,” Journal of Photochemistry and Photobiology A: Chemistry 452 (2024): 115598.

[30] A. Berkdemir, H. R. Gutiérrez, A. R. Botello-Méndez, et al., “Identification of Individual and Few Layers of WS₂ Using Raman Spectroscopy,” Scientific Reports 3 (2013): 1755.

[31] J. A. Wilson and A. D. Yoffe, “The Transition Metal Dichalcogenides Discussion and Interpretation of the Observed Optical, Electrical and Structural Properties,” Advances in Physics 18 (1969): 193–335.

[32] S. Sengupta, S. Peters, T. Sadhukhan, and M. Kundu, “Experimental and Theoretical Insights Into the Supercapacitive Performance of Interconnected WS₂ Nanosheets,” Physical Chemistry Chemical Physics: PCCP 26 (2024): 10301–10309.

[33] Y. Gogotsi and R. M. Penner, “Energy Storage in Nanomaterials - Capacitive, Pseudocapacitive, or Battery-Like?,” ACS Nano 12 (2018): 2081–2083.

[34] V. Augustyn, P. Simon, and B. Dunn, “Pseudocapacitive Oxide Materials for High-Rate Electrochemical Energy Storage,” Energy & Environmental Science 7 (2014): 1597.

[35] E. Erçarıkcı, K. Dağcı Kıranşan, and E. Topçu, “Three-Dimensional ZnCo-MOF Modified Graphene Sponge: Flexible Electrode Material for Symmetric Supercapacitor,” Energy & Fuels 36 (2022): 1735–1745.

[36] X. Yue, R. Hu, D. Zhu, et al., “Controlled Synthesis and Formation Mechanism of Flower-Like CuS/NiS Microspheres for Supercapacitors,” Surfaces and Interfaces 22 (2021): 100871.

[37] K.-J. Huang, L. Wang, Y.-J. Liu, et al., “Layered MoS₂–graphene Composites for Supercapacitor Applications With Enhanced Capacitive Performance,” International Journal of Hydrogen Energy 38 (2013): 14027–14034.

[38] A. De Adhikari, S. Singh, and I. Lahiri, “WS₂@PPy Heterostructured High Performance Supercapacitor Self-Powered by PVDF Piezoelectric Separator,” Journal of Alloys and Compounds 939 (2023): 168713.

[39] S. Ratha and C. S. Rout, “Supercapacitor Electrodes Based on Layered Tungsten Disulfide-Reduced Graphene Oxide Hybrids Synthesized by a Facile Hydrothermal Method,” ACS Applied Materials & Interfaces 5 (2013): 11427–11433.

[40] W. Chen, X. Yu, Z. Zhao, S. Ji, and L. Feng, “Hierarchical Architecture of Coupling Graphene and 2D WS₂ for High-Performance Supercapacitor,” Electrochimica Acta 298 (2019): 313–320.

[41] X. Wang, H. Li, H. Li, et al., “2D/2D 1T-MoS₂/Ti₃C₂ MXene Heterostructure With Excellent Supercapacitor Performance,” Advanced Functional Materials 30 (2020): 0190302.

[42] J. Wang, J. Polleux, J. Lim, and B. Dunn, “Pseudocapacitive Contributions to Electrochemical Energy Storage in TiO₂ (Anatase) Nanoparticles,” Journal of Physical Chemistry C 111 (2007): 14925–14931.

[43] T. Brezesinski, J. Wang, S. H. Tolbert, and B. Dunn, “Ordered Mesoporous α-MoO₃ With Iso-Oriented Nanocrystalline Walls for Thin-Film Pseudocapacitors,” Nature Materials 9 (2010): 146–151.

[44] T. Brezesinski, J. Wang, R. Senter, K. Brezesinski, B. Dunn, and S. H. Tolbert, “On the Correlation Between Mechanical Flexibility, Nanoscale Structure, and Charge Storage in Periodic Mesoporous CeO₂ Thin Films,” ACS Nano 4 (2010): 967–977.

[45] P. L. Taberna, P. Simon, and J. F. Fauvarque, “Electrochemical Characteristics and Impedance Spectroscopy Studies of Carbon-Carbon Supercapacitors,” Journal of the Electrochemical Society 150 (2003): A292.

[46] Y. He, W. Chen, X. Li, et al., “Freestanding Three-Dimensional Graphene/MnO₂ Composite Networks as Ultralight and Flexible Supercapacitor Electrodes,” ACS Nano 7 (2013): 174–182.

[47] R. Devi, J. Patra, K. Tapadia, J.-K. Chang, and T. Maharana, “Arrangement of ZnFe₂O₄@PPy Nanoparticles on Carbon Cloth for Highly Efficient Symmetric Supercapacitor,” Journal of the Taiwan Institute of Chemical Engineers 138 (2022): 104474.

[48] K. S. Morla, T. B. Deshmukh, R. K. Aparna, B. R. Sankapal, and A. Banerjee, “Binder-Free Approach of Mixed-Valent Oxovanadates Anchored on MWCNTs as Supercapacitive Electrodes to Symmetric Supercapacitor Devices: Enriched Performance Through the Incorporation of Guest Molecules in Capsular-Shaped Polyanions,” Energy & Fuels 38 (2024): 21482–21497.

[49] A. A. Kashale, M. M. Vadiyar, S. S. Kolekar, et al., “Binder Free 2D Aligned Efficient MnO₂ Micro Flowers as Stable Electrodes for Symmetric Supercapacitor Applications,” RSC Advances 7 (2017): 36886–36894.

[50] P. Karthika, N. Rajalakshmi, and K. S. Dhathathreyan, “Flexible Polyester Cellulose Paper Supercapacitor With a Gel Electrolyte,” Chemphyschem 14 (2013): 3822–3826.

[51] X. Li, R. Liu, C. Xu, et al., “High-Performance Polypyrrole/Graphene/SnCl₂ Modified Polyester Textile Electrodes and Yarn Electrodes for Wearable Energy Storage,” Advanced Functional Materials 28 (2018): 1800064.

[52] M. B. Idris, B. B. Mamba, and F. Xolile, “Construction of Quasi-Solid-State Supercapacitor With Enhanced High Energy Density Based on Carbon-Rich Graphitic Carbon Nitride and PVA-H₂SO₄ Gel Polymer Electrolyte,” Diamond and Related Materials 160 (2025): 113052.

[53] S. S. Karade, P. Dwivedi, S. Majumder, B. Pandit, and B. R. Sankapal, “First Report on a FeS-Based 2 V Operating Flexible Solid-State Symmetric Supercapacitor Device,” Sustainable Energy & Fuels 1 (2017): 1366–1375.

[54] C. Meng, C. Liu, L. Chen, C. Hu, and S. Fan, “Highly Flexible and All-Solid-State Paperlike Polymer Supercapacitors,” Nano Letters 10 (2010): 4025–4031.

[55] W. Liu, M. Song, B. Kong, and Y. Cui, “Flexible and Stretchable Energy Storage: Recent Advances and Future Perspectives,” Advanced Materials 29 (2017): 1603436.

[56] M. Yang, Y. Zhong, J. Ren, X. Zhou, J. Wei, and Z. Zhou, “Fabrication of High-Power Li-Ion Hybrid Supercapacitors by Enhancing the Exterior Surface Charge Storage,” Advanced Energy Materials 5 (2015): 1500550.

[57] I. S. Ike, I. Sigalas, and S. Iyuke, “Understanding Performance Limitation and Suppression of Leakage Current or Self-Discharge in Electrochemical Capacitors: A Review,” Physical Chemistry Chemical Physics: PCCP 18 (2016): 661–680.

[58] B. E. Conway, V. Birss, and J. Wojtowicz, “The Role and Utilization of Pseudocapacitance for Energy Storage by Supercapacitors,” Journal of Power Sources 66 (1997): 1–14.

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