Acid Ratio-Engineered Carbon Fiber for Enhanced Interfacial Adhesion and Electrochemical Response of Ni-Coated CoVSe Electrodes for Wearable Supercapacitor Applications

Abstract

The development of wearable and flexible electronic gadgets has increased the demand for advanced energy storage systems that can operate under contorted conditions. In this context, carbon fiber cloth (CFC) has attracted considerable attention as a flexible current collector. However, the intrinsically low surface hydrophilicity of CFC limits the uniform growth of electroactive materials. This study focuses on tuning the surface properties of CFC through mixed-acid (HNO₃/H₂SO₄) treatment to enhance its wettability and surface reactivity. As a result, a maximum contact angle of 39.8° was achieved after 100 s of acid mixture treatment. The improved surface wettability enabled the uniform electrodeposition of cobalt vanadium selenide (CVS), forming interconnected nanosheet-like arrays on the optimized CFC substrate. Subsequently, Ni was deposited onto the optimized electrode to introduce additional redox-active sites and promote synergistic electrochemical interactions with the CVS structure, leading to enhanced charge-storage capability. As a result, a maximum areal capacitance of 2300 mF cm^-2 was achieved. The optimized electrode was used as an anode with activated carbon as a cathode to assemble a quasi-solid-state hybrid supercapacitor (QsHSC). The assembled device exhibited capacitance retention and Coulombic efficiency of 93% and 99%, respectively, after 10000 galvanostatic charge–discharge cycles.

Graphical Abstract

Keywords

Quasi-solid-state hybrid supercapacitor / Ni-coated CoVSe / Mixed-acid treatment / Carbon fiber cloth / Wettability tuning / Electrodeposition

References

[1] Umapathi R, Pammi SVN, Han S, Haribabu J, Safarkhani M, Rani GM, Huh YS. Designing smart anti-theft alarm system via lead-free BSFO-PDMS composite based triboelectric nanogenerator. Chem Eng J, 2025, 511 161799

[2] Rani GM, Kim H, Pammi SVN, Umapathi R, Huh YS. Next-generation flexible and wearable triboelectric nanogenerator based on PVDF-HFP@GCN composite for mechanical energy scavenging and sleep pattern detection. Adv Funct Mater, 2025, 36 e19594

[3] Rani GM, Pammi SVN, Kim H, Ahn HS, Hu YC, Jung JH, Umapathi R, Huh YS. Developing real-time IoT-enabled next-generation fire alarm systems using SrBi₄Ti₄O₁₅/PDMS flexible triboelectric nanogenerators. Mater Horiz, 2026, 13: 1465-1476

[4] Sundriyal P, Bhattacharya S. Textile-based supercapacitors for flexible and wearable electronic applications. Sci Rep, 2020, 10 13259

[5] Karthikeyan S, Narenthiran B, Sivanantham A, Bhatlu LD, Maridurai T. Supercapacitor: evolution and review. Mater Today Proc, 2020, 46: 3984-3988

[6] Benoy SM, Pandey M, Bhattacharjya D, Saikia BK. Recent trends in supercapacitor-battery hybrid energy storage devices based on carbon materials. J Energy Storage, 2022, 52 104938

[7] Patil AM, Moon S, Jadhav AA, Hong J, Kang K, Jun SC. Modifying electronic structure of cation-exchanged bimetallic sulfide/metal oxide heterostructure through in situ inclusion of silver (Ag) nanoparticles for extrinsic pseudocapacitor. Adv Funct Mater, 2023, 33 2305264

[8] Patil AM, Moon S, Roy SB, Ha J, Chodankar NR, Dubal DP, Jadhav AA, Guan G, Kang K, Jun SC. Electronic structure engineered heteroatom doped all transition metal sulfide carbon confined heterostructure for extrinsic pseudocapacitor. Small, 2023, 19 2301153

[9] Wilsey MK, Watson KR, Fasusi OC, Yegela BP, Cox CP, Raffaelle PR, Cai L, Müller AM. Selective hydroxylation of carbon fiber paper for long-lasting hydrophilicity by a green chemistry process. Adv Mater Interfaces, 2023, 10: 2201684

[10] Kang L, Liu S, Zhang Q, Zou J, Ai J, Qiao D, Zhong W, Liu Y, Jun SC, Yamauchi Y, Zhang J. Hierarchical spatial confinement unlocking the storage limit of MoS₂ for flexible high-energy supercapacitors. ACS Nano, 2024, 18: 2149-2161

[11] Das SK, Pradhan L, Hong J, Jun SC, Jena BK. Intercalation pseudocapacitance of monolithic microporous carbon thin film scrolls and their battery type behavior. J Power Sources, 2025, 646 237174

[12] Mei T, Gao M, Wang Y, Huang Y, Chu PK. Effects of acid treatment and plasma micromachining on the surface properties of carbon fibers. Appl Surf Sci, 2022, 592: 153261

[13] Marhu PU, Vijeth H. A comparative study of W, V, and Co doping in MoSe₂ for high-performance flexible all-solid-state supercapacitors. RSC Adv, 2025, 15: 26830-26842

[14] Molaei M, Abdollahi M, Zardkhoshoui AM, Davarani SSH. Advancements in energy storage: combining hollow iron cobalt selenide spheres with nickel cobalt layered double hydroxide nanosheets. J Energy Storage, 2024, 85: 111079

[15] Hong J, Kang L, Patil AM, Joo J, Lim S, Yeom J, Kim T, Das SK, Min J, Islam M, Yoon T, Jun SC. Self-assembled Cu3P@NiCo₂O₄ core-shell heterostructure electrodes for high-energy all-solid-state supercapacitor. Small, 2025, 21: e08090

[16] Seong J, Patil AM, Roy SB, Lee J, Jun SC. N-doped oxygen vacancy-rich NiCo₂O₄ nanoarrays for supercapacitor and non-enzymatic glucose sensing. Int J Energy Res, 2022, 46: 24501-24515

[17] Moorthi K, Padaki M, Mohan S. 2D–3D-structured mixed-metal cobalt-vanadium-selenide (Co-V-Se) system: a transformative electrode material for supercapacitors. ACS Appl Energy Mater, 2025, 8: 11910-11924

[18] Sakthivel M, Ramaraj S, Chen SM, Ho KC. Bimetallic vanadium cobalt diselenide nanosheets with additional active sites for excellent asymmetric pseudocapacitive performance: comparing the electrochemical performances with M-CoSe₂ (M = Zn, Mn, and Cu). J Mater Chem A Mater, 2019, 7: 12565-12581

[19] Kirubasankar B, Palanisamy P, Arunachalam S, Murugadoss V, Angaiah S. 2D MoSe₂-Ni(OH)₂ nanohybrid as an efficient electrode material with high rate capability for asymmetric supercapacitor applications. Chem Eng J, 2019, 355: 881-890

[20] Hao C, Wen F, Xiang J, Wang L, Hou H, Su Z, Hu W, Liu Z. Erratum: Controlled incorporation of Ni(OH)₂ nanoplates into flowerlike MoS₂ nanosheets for flexible all-solid-state supercapacitors. Adv Funct Mater, 2014, 24: 6700-6707

[21] Kitada A. Electrodeposition of metal foils for battery current collectors: Status and challenges. Energy Storage Mater, 2025, 75: 104073

[22] Kumar SA, Sahoo S, Laxminarayana GK, Rout CS. Electrochemical deposition for cultivating nano- and microstructured electroactive materials for supercapacitors: recent developments and future perspectives. Small, 2024, 20: 2402087

[23] Shankar EG, Das AK, Yu JS. Surface-engineered binder-free PEDOT shielded nickel magnesium selenide nanosheet arrays electrode for ultralong-life flexible quasi-solid-state hybrid supercapacitors. J Magnes Alloys, 2023, 11: 1802-1814

[24] Shankar EG, Das AK, Yu JS. Biomass-derived ant colony-like ion diffused redox porous carbon toward economical and high-performance quasi-solid-state supercapacitor. Int J Energy Res, 2022, 46: 1593-1608

[25] Qiu C, Jiang L, Gao Y, Sheng L. Effects of oxygen-containing functional groups on carbon materials in supercapacitors: a review. Mater Des, 2023, 230: 111952

[26] Razavifar M, Abdi A, Nikooee E, Aghili O, Riazi M. Quantifying the impact of surface roughness on contact angle dynamics under varying conditions. Sci Rep, 2025, 15: 16611

[27] Afkhami A, Madrakian T, Karimi Z. The effect of acid treatment of carbon cloth on the adsorption of nitrite and nitrate ions. J Hazard Mater, 2007, 144: 427-431

[28] Datsyuk V, Kalyva M, Papagelis K, Parthenios J, Tasis D, Siokou A, Kallitsis I, Galiotis C. Chemical oxidation of multiwalled carbon nanotubes. Carbon NY, 2008, 46: 833-840

[29] Yuan R, Guo Y, Gurgan I, Siddique N, Li YS, Jang S, Noh GA, Kim SH. Raman spectroscopy analysis of disordered and amorphous carbon materials: a review of empirical correlations. Carbon NY, 2025, 238: 120214

[30] Zhang J, Zou H, Qing Q, Yang Y, Li Q, Liu Z, Guo X, Du Z. Effect of chemical oxidation on the structure of single-walled carbon nanotubes. J Phys Chem B, 2003, 107: 3712-3718

[31] Porto AB, de Oliveira LFC, Dos Santos HF. Exploring the potential energy surface for reaction of SWCNT with NO²⁺: a model reaction for oxidation of carbon nanotube in acid solution. Comput Theor Chem, 2016, 1088: 1-8

[32] Yang X, Wan Y, Zheng Y, He F, Yu Z, Huang J, Wang H, Ok YS, Jiang Y, Gao B. Surface functional groups of carbon-based adsorbents and their roles in the removal of heavy metals from aqueous solutions: a critical review. Chem Eng J, 2019, 366: 608-621

[33] Xu Z, Chen L, Huang Y, Li J, Wu X, Li X, Jiao Y. Wettability of carbon fibers modified by acrylic acid and interface properties of carbon fiber/epoxy. Eur Polym J, 2008, 44: 494-503

[34] Jerigová M, Odziomek M, López-Salas N. “We are here!” oxygen functional groups in carbons for electrochemical applications. ACS Omega, 2022, 7: 11544-11554

[35] Cooper ER, Li M, Gentle I, Xia Q, Knibbe R. A deeper understanding of metal nucleation and growth in rechargeable metal batteries through theory and experiment. Angew Chem Int Ed, 2023, 62: e202309247

[36] Layachi OA, Moujib A, Khoumri EM. Electrochemical nucleation and growth mechanism of Metals. Electroanalysis, 2024, 36: e202400115

[37] Panith P, Butnoi P, Intasanta V. The hybrid structure of nanoflower-like Co_xMn_yNi_zO₄ nanoparticles embedded biomass-lignin carbon nanofibers as free-standing and binder-free electrodes for high performance supercapacitors. J Alloys Compd, 2022, 918: 165659

[38] Luo G, Yuan Y, Cai J, Yuan G, Li N. The establishment of current transient of nucleation and growth under diffusion-controlled electrocrystallisation: a microreview. Coatings, 2024, 14: 62

[39] Zhang F, Liu S, Wang F. Nucleation and growth behaviors of nickel coating by jet electrodeposition under the combined effect of convection and vertical distribution. J Phys Chem C, 2022, 126: 14669-14679

[40] Wary RR, Das A, Amirov ES, Liu D, Gumber S, Kazakova EA, Vasenko AS, Prezhdo OV. Highly oriented nitrogen-doped flower-like ZnO nanostructures for boosting photocatalytic and photoelectrochemical performance: a combined experimental and DFT Study. J Phys Chem Lett, 2025, 16: 5180-5187

[41] Bogachuk D, Baretzky C, Eckert J, Yang B, Suo J, Dangudubiyyam UK, Loukeris G, Mohammadzadeh H, Kluska S, Kohlstädt M, Würfel U. Rethinking electrochemical deposition of nickel oxide for photovoltaic applications. Solar RRL, 2024, 8: 2300750

[42] Fang G, Cai J, Huang Z, Zhang C. One-step electrodeposition of cerium-doped nickel hydroxide nanosheets for effective oxygen generation. RSC Adv, 2019, 9: 17891-17896

[43] Rathore D, Sharma MD, Sharma A, Basu M, Pande S. Aggregates of Ni/Ni(OH)₂/NiOOH nanoworms on carbon cloth for electrocatalytic hydrogen evolution. Langmuir, 2020, 36: 14019-14030

[44] Yu TT, Liu HL, Huang M, Zhang JH, Su DQ, Tang ZH, Xie JF, Liu YJ, Yuan AH, Kong QH. Zn₂GeO₄ nanorods grown on carbon cloth as high performance flexible lithium-ion battery anodes. RSC Adv, 2017, 7: 51807-51813

[45] Shankar EG, Kiran AS, Paranjape MV, Yu JS. Polymer matrix-assisted commercial-level mass loading of porous cobalt manganese nitride towards high-performance binder-free electrodes for hybrid supercapacitors. J Mater Chem A, 2024, 12: 25860-25874

[46] Chen X, Jiang R, Dong C, Liu H, Yang J, Du X. Polycrystalline CoO-Co9S8 heterostructure nanoneedle arrays as bifunctional catalysts for efficient overall water splitting. ChemElectroChem, 2022, 9: e202101566

[47] Gupta S, Fernandes R, Patel R, Spreitzer M, Patel N. A review of cobalt-based catalysts for sustainable energy and environmental applications. Appl Catal A Gen, 2023, 661: 119254

[48] Prześniak-Welenc M, Nadolska M, Jurak K, Li J, Górnicka K, Mielewczyk-Gryń A, Rutkowska M, Nowak AP. The valance state of vanadium-key factor in the flexibility of potassium vanadates structure as cathode materials in Li-ion batteries. Sci Rep, 2022, 12: 18751

[49] Shankar EG, Das AK, Yu JS. Facile one-step electrodeposition synthesis of binder-free CoxFe_3-xSe₄ ultrathin nanosheet arrays towards high-performance quasi-solid-state supercapacitors. Appl Surf Sci, 2022, 596: 153613

[50] Umapathi S, Masud J, Swesi AT, Nath M. FeNi2Se4-reduced graphene oxide nanocomposite: enhancing bifunctional electrocatalytic activity for oxygen evolution and reduction through synergistic effects. Adv Sustain Syst, 2017, 1: 1700086

[51] Li Z, Shi C, Yu J, Bai L. Surface oxidation of α-Ni(OH)₂ nanowires to boost energy storage capability for supercapacitors. Appl Surf Sci, 2024, 669: 160534

[52] Das AK, Ramulu B, Shankar EG, Yu JS. Binder-free CuS@PEDOT and Co-V-Se electrodes for flexible quasi-solid-state asymmetric supercapacitor. Chem Eng J, 2022, 429 132486

[53] Karaman O, Ceyran E, Kariper SEB, Kariper İA, Karaman C. High-energy X-ray irradiation-induced functionalization of Ni(OH)₂ for enhanced supercapacitor electrodes. Sci Rep, 2025, 15 29194

[54] Yi X, Sun H, Robertson N, Kirk C. Nanoflower Ni(OH)₂grownin situon Ni foam for high-performance supercapacitor electrode materials. Sustain Energy Fuels, 2021, 5: 5236-5246

[55] Moya AA. Comparing the characteristic frequencies of the transmissive and reflexive finite-length Warburg diffusion processes. J Electroanal Chem, 2023, 929: 117132

[56] Xiao J, Cao X, Gridley B, Golden W, Ji Y, Johnson S, Lu D, Lin F, Liu J, Liu Y, Liu Z, Ramesh HN, Shi F, Schrooten J, Sims MJ, Sun S, Shao Y, Vaisman A, Yang J, Whittingham MS. From mining to manufacturing: scientific challenges and opportunities behind battery production. Chem Rev, 2025, 125: 6397-6431

[57] Wadodkar NA, Salunke RS, Pawar SK, Umar A, Ibrahim AA, Akbar S, Ansari SA, Baskoutas S, Shirale DJ. Next-generation supercapacitors: advances in binder-free electrodes, scalable fabrication, and emerging applications. Adv Sustain Syst, 2025, 10: e00599

Funding

Ministry of Science and ICT, South Korea(RS-2024-00339770)

Ministry of Environment(ARQ202101038001)

RIGHTS & PERMISSIONS

Donghua University, Shanghai, China