Additive-Free Ti₃C₂T_x MXene/Carbon Nanotube Aqueous Inks Enable Energy Density Enriched 3D-Printed Flexible Micro-Supercapacitors for Modular Self-Powered Systems

Abstract

3D-printed Ti₃C₂T_x MXene-based interdigital micro-supercapacitors (MSCs) have great potential as energy supply devices in the field of microelectronics due to their short ion diffusion path, high conductivity, excellent pseudocapacitance, and fast charging capabilities. However, searching for eco-friendly aqueous Ti₃C₂T_x MXene-based inks without additives and preventing severe restack of MXene nanosheets in high-concentration inks are significantly challenging. This study develops an additive-free, highly printable, viscosity adjustable, and environmentally friendly MXene/carbon nanotube (CNT) hybrid aqueous inks, in which the CNT can not only adjust the viscosity of Ti₃C₂T_x MXene inks but also widen the interlayer spacing of adjacent Ti₃C₂T_x MXene nanosheets effectively. The optimized MXene/CNT composite inks are successfully adopted to construct various configurations of MSCs with remarkable shape fidelity and geometric accuracy, together with enhanced surface area accessibility for electrons and ions diffusion. As a result, the constructed interdigital symmetrical MSCs demonstrate outstanding areal capacitance (1249.3 mF cm⁻²), superior energy density (111 μWh cm⁻² at 0.4 mW cm⁻²), and high power density (8 mW cm⁻² at 47.1 μWh cm⁻²). Furthermore, a self-powered modular system of solar cells integrated with MXene/CNT-MSCs and pressure sensors is successfully tailored, simultaneously achieving efficient solar energy collection and real-time human activities monitoring. This work offers insight into the understanding of the role of CNTs in MXene/CNT ink. Moreover, it provides a new approach for preparing environmentally friendly MXene-based inks for the 3D printing of high-performance MSCs, contributing to the development of miniaturized, flexible, and self-powered printable electronic microsystems.

Keywords

3D-printing / flexible micro-supercapacitors / self-powered systems / Ti₃C₂T_x MXene

References

[1] H. Zhang, Q. Yang, L. Xu, et al., “Triboelectric Nanogenerators Based on Hydrated Lithium Ions Incorporated Double-Network Hydrogels for Biomechanical Sensing and Energy Harvesting at Low Temperature,” Nano Energy 125 (2024): 109521.

[2] T. Gao, N. Li, Y. Yang, et al., “Mechanical Reliable, NIR Light-Induced Rapid Self-Healing Hydrogel Electrolyte Towards Flexible Zinc-Ion Hybrid Supercapacitors With Low-Temperature Adaptability and Long Service Life,” Journal of Energy Chemistry 92 (2024): 63-73.

[3] X. Xu, Y. Chen, P. He, et al., “Wearable CNT/Ti₃C₂T_x MXene/PDMS Composite Strain Sensor With Enhanced Stability for Real-Time Human Healthcare Monitoring,” Nano Research 14, no. 8 (2021): 2875-2883.

[4] S. Liu, Y. Zhao, H. Li, and J. Yang, “One-Step Synthesis of Porous Nickel-Aluminum Layered Double Hydroxide With Oxygen Defects for High-Performance Supercapacitor Electrode,” Journal of Central South University 30, no. 12 (2023): 4138-4148.

[5] H. Li, H. Guo, S. Tong, et al., “High-Performance Supercapacitor Carbon Electrode Fabricated by Large-Scale Roll-to-Roll Micro-Gravure Printing,” Journal of Physics D: Applied Physics 52, no. 11 (2019): 115501.

[6] T. Gao, W. Luo, Y. Yang, et al., “Engineering Hierarchically Porous Carbon Nanorods Electrode Materials for High Performance Zinc Ion Hybrid Supercapacitors,” Colloids and Surfaces, A: Physicochemical and Engineering Aspects 684 (2024): 133057.

[7] Y. Yang, Y. Zhou, P. Ji, P. Yang, J. Xu, and N. Li, “Zinc-Ion Hybrid Supercapacitors with Hierarchically N-Doped Porous Carbon Electrodes and ZnSO₄/ZnI₂ Redox Electrolyte Exhibit Boosted Energy Density,” Colloids and Surfaces, A: Physicochemical and Engineering Aspects 694 (2024): 134122.

[8] J. Xu, H. Zhang, Z. Guo, et al., “Fully Physical Crosslinked Bsa-Based Conductive Hydrogels With High Strength and Fast Self-Recovery for Human Motion and Wireless Electrocardiogram Sensing,” International Journal of Biological Macromolecules 230 (2023): 123195.

[9] S. Zheng, H. Wang, P. Das, et al., “Multitasking MXene Inks Enable High-Performance Printable Microelectrochemical Energy Storage Devices for All-Flexible Self-Powered Integrated Systems,” Advanced Materials 33, no. 10 (2021): 2005449.

[10] J. Zeng, L. Dong, L. Sun, et al., “Printable Zinc-Ion Hybrid Micro-Capacitors for Flexible Self-Powered Integrated Units,” Nano-Micro Letters 13 (2021): 19.

[11] S. H. Park, G. Goodall, and W. S. Kim, “Perspective on 3D-Designed Micro-Supercapacitors,” Materials & Design 193 (2020): 108797.

[12] S. Wang, J. Ma, X. Shi, Y. Zhu, and Z. S. Wu, “Recent Status and Future Perspectives of Ultracompact and Customizable Micro-Supercapacitors,” Nano Research Energy 1, no. 2 (2022): e9120018.

[13] M. Li, S. Zhou, L. Cheng, et al., “3D Printed Supercapacitor: Techniques, Materials, Designs, and Applications,” Advanced Functional Materials 33, no. 1 (2023): 2208034.

[14] J. Qin, H. Zhang, Z. Yang, et al., “Recent Advances and Key Opportunities on In-Plane Micro-Supercapacitors: From Functional Microdevices to Smart Integrated Microsystems,” Journal of Energy Chemistry 81 (2023): 410-431.

[15] S. Wang, L. Li, S. Zheng, et al., “Monolithic Integrated Micro-Supercapacitors With Ultra-High Systemic Volumetric Performance and Areal Output Voltage,” National Science Review 10, no. 3 (2023): nwac271.

[16] A. Khodabandehlo, A. Noori, M. S. Rahmanifar, M. F. El-Kady, R. B. Kaner, and M. F. Mousavi, “Laser-Scribed Graphene-Polyaniline Microsupercapacitor for Internet-of-Things Applications,” Advanced Functional Materials 32, no. 39 (2022): 2204555.

[17] L. E. Chaney, W. J. Hyun, M. Khalaj, et al., “Fully Printed, High-Temperature Micro-Supercapacitor Arrays Enabled by a Hexagonal Boron Nitride Ionogel Electrolyte,” Advanced Materials 35 (2023): 2305161.

[18] J. Qin, J. Gao, X. Shi, et al., “Hierarchical Ordered Dual-Mesoporous Polypyrrole/Graphene Nanosheets as Bi-Functional Active Materials for High-Performance Planar Integrated System of Micro-Supercapacitor and Gas Sensor,” Advanced Functional Materials 30, no. 16 (2020): 1909756.

[19] Y. Liu, S. Zheng, J. Ma, et al., “Aqueous High-Voltage All 3D-Printed Micro-Supercapacitors With Ultrahigh Areal Capacitance and Energy Density,” Journal of Energy Chemistry 63 (2021): 514-520.

[20] Z. Lyu, G. J. H. Lim, J. J. Koh, et al., “Design and Manufacture of 3D-Printed Batteries,” Joule 5, no. 1 (2021): 89-114.

[21] M. Pei, H. Shi, F. Yao, et al., “3D Printing of Advanced Lithium Batteries: A Designing Strategy of Electrode/Electrolyte Architectures,” Journal of Materials Chemistry A 9, no. 45 (2021): 25237-25257.

[22] Z. Fan, J. Jin, C. Li, et al., “3D-printed Zn-Ion Hybrid Capacitor Enabled by Universal Divalent Cation-Gelated Additive-Free Ti₃C₂ MXene Ink,” ACS Nano 15, no. 2 (2021): 3098-3107.

[23] L. Zhang, J. Qin, P. Das, et al., “Electrochemically Exfoliated Graphene Additive-Free Inks for 3D Printing Customizable Monolithic Integrated Micro-Supercapacitors on a Large Scale,” Advanced Materials 36, no. 19 (2024): 2313930.

[24] J. Ge, J. Meng, L. Zhang, et al., “Inducing Directional Charge Delocalization in 3D-Printable Micro-Supercapacitors Based on Strongly Coupled Black Phosphorus and ReS₂ Nanocomposites,” Small 20 (2024): 2312019.

[25] Y. Zhu, Q. Zhang, J. Ma, et al., “Three-Dimensional (3D)-Printed Mxene High-Voltage Aqueous Micro-Supercapacitors With Ultrahigh Areal Energy Density and Low-Temperature Tolerance,” Carbon Energy 6 (2024): e481.

[26] M. Gao, F. Wang, S. Yang, et al., “Engineered 2D MXene-Based Materials for Advanced Supercapacitors and Micro-Supercapacitors,” Materials Today 72 (2023): 318-358.

[27] Y. Z. Zhang, Y. Wang, Q. Jiang, J. K. El-Demellawi, H. Kim, and H. N. Alshareef, “MXene Printing and Patterned Coating for Device Applications,” Advanced Materials 32, no. 21 (2020): 1908486.

[28] K. R. G. Lim, M. Shekhirev, B. C. Wyatt, B. Anasori, Y. Gogotsi, and Z. W. Seh, “Fundamentals of MXene Synthesis,” Nature Synthesis 1, no. 8 (2022): 601-614.

[29] D. Meng, M. Xu, S. Li, et al., “Functional MXenes: Progress and Perspectives on Synthetic Strategies and Structure-Property Interplay for Next-Generation Technologies,” Small 20, no. 4 (2024): 2304483.

[30] J. Liang, C. Jiang, and W. Wu, “Printed Flexible Supercapacitor: Ink Formulation, Printable Electrode Materials and Applications,” Applied Physics Reviews 8, no. 2 (2021): 021319.

[31] C. Zhang, L. McKeon, M. P. Kremer, et al., “Additive-Free Mxene Inks and Direct Printing of Micro-Supercapacitors,” Nature Communications 10, no. 1 (2019): 1795.

[32] H. Huang and W. Yang, “MXene-Based Micro-Supercapacitors: Ink Rheology, Microelectrode Design and Integrated System,” ACS Nano 18, no. 6 (2024): 4651-4682.

[33] J. Ma, S. Zheng, Y. Cao, et al., “Aqueous MXene/PH1000 Hybrid Inks for Inkjet-Printing Micro-Supercapacitors With Unprecedented Volumetric Capacitance and Modular Self-Powered Microelectronics,” Advanced Energy Materials 11, no. 23 (2021): 2100746.

[34] P. Zhang, J. Li, D. Yang, R. A. Soomro, and B. Xu, “Flexible Carbon Dots-Intercalated MXene Film Electrode With Outstanding Volumetric Performance for Supercapacitors,” Advanced Functional Materials 33, no. 1 (2023): 2209918.

[35] J. Yang, T. Wang, X. Guo, et al., “Flexible Sodium-Ion Capacitors Boosted by High Electrochemically-Reactive and Structurally-Stable Sb₂S₃ Nanowire/Ti₃C₂T_x Mxene Film Anodes,” Nano Research 16, no. 4 (2023): 5592-5600.

[36] L. Liu, J. Lu, X. Long, et al., “3D Printing of High-Performance Micro-Supercapacitors With Patterned Exfoliated Graphene/Carbon Nanotube/Silver Nanowire Electrodes,” Science China: Technological Sciences 64, no. 5 (2021): 1065-1073.

[37] H. Zhou, Y. Sun, H. Yang, et al., “Co₃O₄ Quantum Dots Intercalation Liquid-Crystal Ordered-Layered-Structure Optimizing the Performance of 3D-Printing Micro-Supercapacitors,” Advanced Science 10, no. 33 (2023): 2303636.

[38] G. Zhou, X. Liu, C. Liu, et al., “3D Printed MXene-Based Films and Cellulose Nanofiber Reinforced Hydrogel Electrolyte to Enable High-Performance Flexible Supercapacitors,” Journal of Materials Chemistry A 12, no. 6 (2024): 3734-3744.

[39] L. Yu, Z. Fan, Y. Shao, Z. Tian, J. Sun, and Z. Liu, “Versatile N-Doped MXene Ink for Printed Electrochemical Energy Storage Application,” Advanced Energy Materials 9, no. 34 (2019): 1901839.

[40] Q. Wang, Y. Fang, and M. Cao, “Constructing MXene-PANI@ MWCNTs Heterojunction With High Specific Capacitance Towards Flexible Micro-Supercapacitor,” Nanotechnology 33, no. 29 (2022): 295401.

[41] T. Xue, Y. Yang, D. Yu, et al., “3D Printed Integrated Gradient-Conductive MXene/CNT/Polyimide Aerogel Frames for Electromagnetic Interference Shielding With Ultra-Low Reflection,” Nano-Micro Letters 15, no. 1 (2023): 45.

[42] L. Yu, W. Li, C. Wei, Q. Yang, Y. Shao, and J. Sun, “3D Printing of NiCoP/Ti₃C₂ MXene Architectures for Energy Storage Devices With High Areal and Volumetric Energy Density,” Nano-Micro Letters 12 (2020): 143.

[43] Z. Wang, Z. Huang, H. Wang, et al., “3D-printed Sodiophilic V₂CT_x/rGO-CNT MXene Microgrid Aerogel for Stable Na Metal Anode With High Areal Capacity,” ACS Nano 16, no. 6 (2022): 9105-9116.

[44] M. Hou, M. Yu, W. Liu, et al., “Mxene Hybrid Conductive Hydrogels With Mechanical Flexibility, Frost-Resistance, Photothermoelectric Conversion Characteristics and Their Multiple Applications in Sensing,” Chemical Engineering Journal 483 (2024): 149299.

[45] T. Huang, B. Gao, S. Zhao, et al., “All-MXenes Zinc Ion Hybrid Micro-Supercapacitor With Wide Voltage Window Based on V₂CT_x Cathode and Ti₃C₂T_x Anode,” Nano Energy 111 (2023): 108383.

[46] X. Yan, Y. Tong, X. Wang, F. Hou, and J. Liang, “Extrusion-Based 3D-Printed Supercapacitors: Recent Progress and Challenges,” Energy & Environmental Materials 5, no. 3 (2022): 800-822.

[47] L. Li, J. Meng, X. Bao, et al., “Direct-Ink-Write 3D Printing of Programmable Micro-Supercapacitors From MXene-Regulating Conducting Polymer Inks,” Advanced Energy Materials 13, no. 9 (2023): 2203683.

[48] G. Zhou, M. C. Li, C. Liu, C. Liu, Z. Li, and C. Mei, “3D Printed Nitrogen-Doped Thick Carbon Architectures for Supercapacitor: Ink Rheology and Electrochemical Performance,” Advanced Science 10, no. 10 (2023): 2206320.

[49] Y. Liu, S. Zheng, J. Ma, et al., “All 3D Printing Shape-Conformable Zinc Ion Hybrid Capacitors With Ultrahigh Areal Capacitance and Improved Cycle Life,” Advanced Energy Materials 12, no. 27 (2022): 2200341.

[50] G. Shi, Y. Zhu, M. Batmunkh, et al., “Cytomembrane-Inspired MXene Ink With Amphiphilic Surfactant for 3D Printed Microsupercapacitors,” ACS Nano 16, no. 9 (2022): 14723-14736.

[51] S. Zhang, H. Ying, B. Yuan, R. Hu, and W. Q. Han, “Partial Atomic Tin Nanocomplex Pillared Few-Layered Ti₃C₂T_x MXenes for Superior Lithium-Ion Storage,” Nano-Micro Letters 12 (2020): 78.

[52] Z. Cao, J. Fu, M. Wu, T. Hua, and H. Hu, “Synchronously Manipulating Zn²⁺ Transfer and Hydrogen/Oxygen Evolution Kinetics in MXene Host Electrodes Toward Symmetric Zn-Ions Micro-Supercapacitor With Enhanced Areal Energy Density,” Energy Storage Materials 40 (2021): 10-21.

[53] G. Zhou, M. C. Li, C. Liu, Q. Wu, and C. Mei, “3D Printed Ti₃C₂T_x MXene/Cellulose Nanofiber Architectures for Solid-State Supercapacitors: Ink Rheology, 3D Printability, and Electrochemical Performance,” Advanced Functional Materials 32, no. 14 (2022): 2109593.

[54] S. Guan, Y. Yang, Y. Wang, et al., “A Dual-Functional MXene-Based Bioanode for Wearable Self-Charging Biosupercapacitors,” Advanced Materials 36, no. 1 (2024): 2305854.

[55] G. Wang, R. Zhang, H. Zhang, and K. Cheng, “Aqueous MXene Inks for Inkjet-Printing Microsupercapacitors With Ultrahigh Energy Densities,” Journal of Colloid and Interface Science 645 (2023): 359-370.

[56] J. Li, H. Wang, and X. Xiao, “Intercalation in Two-Dimensional Transition Metal Carbides and Nitrides (MXenes) Toward Electrochemical Capacitor and Beyond,” Energy & Environmental Materials 3, no. 3 (2020): 306-322.

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