Thin-walled hollow fibers for flexible high energy density fiber-shaped supercapacitors

Abstract

Fiber-shaped supercapacitors, which occupy minimal volume and possess remarkable flexibility, are particularly promising candidates for next-generation smart wearable devices. However, the state-of-the-art energy density and mechanical properties of fiber-shaped electrodes are far from satisfactory. Herein, hollow poly(3,4-ethylenedioxythiophene):polystyrene sulfonate thin-walled fibers (HPFs) are continuously prepared by coaxial wet-spinning. These HPFs combine a simple and high continuous preparation with high electrochemical performance and flexibility, owing to their hollow nature, small diameter (125 μm) and thin wall structure (8 μm). As a result, the HPFs display a specific areal capacitance of 115.2 mF cm^-2 at a current density of 0.3 mA cm^-2 with a high energy density of 9 μWh cm^-2 at a power density of 0.112 mW cm^-2. Furthermore, the HPFs maintain 81% of the initial capacitance after 10,000 cycles with ~100% Coulombic efficiency. More importantly, the specific capacitance is almost completely maintained after bending 3000 times at 180°.

Keywords

Fiber-shaped supercapacitors / PEDOT:PSS / energy density / flexible

References

[1] Pan Z,Zhang Y,Wang J.Quasi-solid-state fiber-shaped aqueous energy storage devices: recent advances and prospects.J Mater Chem A2020;8:6406-33

[2] Wang L,He J.Application challenges in fiber and textile electronics.Adv Mater2020;32:e1901971

[3] Manjakkal L,Yogeswaran N,Dahiya R.A wearable supercapacitor based on conductive PEDOT:PSS-coated cloth and a sweat electrolyte.Adv Mater2020;32:e1907254

[4] Lai Y,Wu H.Elastic multifunctional liquid-metal fibers for harvesting mechanical and electromagnetic energy and as self-powered sensors.Adv Energy Mater2021;11:2100411

[5] Yang J,Pan Z.All-solid-state high-energy asymmetric supercapacitors enabled by three-dimensional mixed-valent MnOx nanospike and graphene electrodes.ACS Appl Mater Interfaces2015;7:22172-80

[6] Zhu M,Li H.Light-permeable, photoluminescent microbatteries embedded in the color filter of a screen.Energy Environ Sci2018;11:2414-22

[7] Ma W,Pan S.Smart fibers for energy conversion and storage.Chem Soc Rev2021;50:7009-61

[8] Lee C,Lin C.A paper-based electrode using a graphene dot/PEDOT:PSS composite for flexible solar cells.Nano Energy2017;36:260-7

[9] Song W,Xu B.All-solution-processed metal-oxide-free flexible organic solar cells with over 10% efficiency.Adv Mater2018;30:e1800075

[10] Tian J,Chen P,Chen X.High-performance wearable supercapacitors based on PANI/N-CNT@CNT fiber with a designed hierarchical core-sheath structure.J Mater Chem A2021;9:20635-44

[11] Yang Z,Niu Y.One-step wet-spinning assembly of twisting-structured graphene/carbon nanotube fiber supercapacitor.Journal of Energy Chemistry2020;51:434-41

[12] Yuan D,Cheng J.Twisted yarns for fiber-shaped supercapacitors based on wetspun PEDOT:PSS fibers from aqueous coagulation.J Mater Chem A2016;4:11616-24

[13] Wang Z,Guan Q.All-in-one fiber for stretchable fiber-shaped tandem supercapacitors.Nano Energy2018;45:210-9

[14] Zhang L,Zhang F.Controlling the effective surface area and pore size distribution of sp2 carbon materials and their impact on the capacitance performance of these materials.J Am Chem Soc2013;135:5921-9

[15] Ma W,Li M.Unzipped carbon nanotube/graphene hybrid fiber with less “dead volume” for ultrahigh volumetric energy density supercapacitors.Adv Funct Mater2021;31:2100195

[16] Qu G,Li X.A fiber supercapacitor with high energy density based on hollow graphene/conducting polymer fiber electrode.Adv Mater2016;28:3646-52

[17] Jalili R,Innis PC.One-step wet-spinning process of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) fibers and the origin of higher electrical conductivity.Adv Funct Mater2011;21:3363-70

[18] Kim N,Lee SH.Highly conductive PEDOT:PSS nanofibrils induced by solution-processed crystallization.Adv Mater2014;26:2268-72, 2109

[19] Lang U,Naujoks N.Microscopical Investigations of PEDOT:PSS thin films.Adv Funct Mater2009;19:1215-20

[20] Vosgueritchian M,Bao Z.Highly conductive and transparent PEDOT:PSS films with a fluorosurfactant for stretchable and flexible transparent electrodes.Adv Funct Mater2012;22:421-8

[21] Cai S,Chen H,Gopalsamy K.Wet-spinning of ternary synergistic coaxial fibers for high performance yarn supercapacitors.J Mater Chem A2017;5:22489-94

[22] Xu D,Wang W.Effect of H₂SO₄ solution treatment on adhesion, charge transfer, and catalytic performance of screen-printed PEDOT:PSS.Chemphyschem2019;20:374-82

[23] Li Y,Zhang Z.A strong and highly flexible aramid nanofibers/PEDOT:PSS film for all-solid-state supercapacitors with superior cycling stability.J Mater Chem A2016;4:17324-32

[24] Alemu D,Ho K.Highly conductive PEDOT:PSS electrode by simple film treatment with methanol for ITO-free polymer solar cells.Energy Environ Sci2012;5:9662

[25] Xu T,Zhang S,Zhang M.Antifreezing and stretchable all-gel-state supercapacitor with enhanced capacitances established by graphene/PEDOT-polyvinyl alcohol hydrogel fibers with dual networks.Carbon2021;171:201-10

[26] Xu H,Sun Y,Liu X.Flexible fiber-shaped supercapacitors based on hierarchically nanostructured composite electrodes.Nano Res2015;8:1148-58

[27] Li B,Wang Z,Ni W.Highly-wrinkled reduced graphene oxide-conductive polymer fibers for flexible fiber-shaped and interdigital-designed supercapacitors.J Power Sources2018;376:117-24

[28] Sun P,Wang Z.Rational design of carbon shell endows TiN@C nanotube based fiber supercapacitors with significantly enhanced mechanical stability and electrochemical performance.Nano Energy2017;31:432-40

[29] Noh J,Kim YK.High performance asymmetric supercapacitor twisted from carbon fiber/MnO₂ and carbon fiber/MoO₃.Carbon2017;116:470-8

[30] Kou L,Zheng B.Coaxial wet-spun yarn supercapacitors for high-energy density and safe wearable electronics.Nat Commun2014;5:3754 PMCID:PMC4024741

[31] Sun G,Lin R,Zhang H.Hybrid fibers made of molybdenum disulfide, reduced graphene oxide, and multi-walled carbon nanotubes for solid-state, flexible, asymmetric supercapacitors.Angew Chem Int Ed Engl2015;54:4651-6

[32] Meng C,He J.Wet-spinning fabrication of multi-walled carbon nanotubes reinforced poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) hybrid fibers for high-performance fiber-shaped supercapacitor.J Mater Sci: Mater Electron2020;31:19293-308

[33] Wang H,Jian M.Superelastic wire-shaped supercapacitor sustaining 850% tensile strain based on carbon nanotube@graphene fiber.Nano Res2018;11:2347-56