Robust MXene fiber empowered by rational formulation of spinning stock and optimization of interfacial cross-linking for efficient charge storage

Ti 3 C 2 T X nanosheets are promising candidates upon the increasing demands of flexible electrode materials for advancing portable/wearable fibrous energy storage devices because of their outstanding electrical conductivity and high theoretical capacitance; nevertheless, the weak interlayer interaction and the requirement of suitable interlayer spacing make it difficult to develop strong MXene fibers with desirable charge storage ability. Herein, we develop a robust MXene fiber optimized by interfacial cross-linking through directly coagulating the rationally formulated spinning stock of Ti 3 C 2 T X nanosheets, polyvinyl alcohol and glutaraldehyde (MXene-PVA-GA, denoted as MPG) in acetic acid. The modified fibers demonstrate significantly enhanced mechanical strength, reaching 176.5 MPa, while maintaining a capacitance up to 1225.0 F cm −3 at 4 A cm −3 , outperforming the pure MXene fibers (26 MPa and 647.0 F cm −3 ). The fabricated FSC achieves a volumetric capacitance reaching 281.0 F cm −3 at 1 A cm −3 , and an energy density up to 0.065 Wh cm −3 under a power density of 7.2 W cm −3 , underscoring its feasibility for deployment in flexible and smart wearable technologies. This work offers valuable guidance for developing robust MXene-based fibers with enhanced mechanical properties and electrochemical performance, supporting future applications in wearable and textile supercapacitors. We develop a robust MXene fiber optimized by interfacial cross-linking through directly coagulating the mixed spinning stock of MXene, polyvinyl alcohol and glutaraldehyde (MXene-PVA-GA, denoted as MPG) in acetic acid. PVA acts as plasticizer through forming hydrogen bonds with Ti 3 C 2 T X , while GA serves as crosslinker to establish chemical bonds with PVA and Ti 3 C 2 T X , thereby enhancing the overall strength of fibers. Simultaneous improvement in tensile strength, output capacitance, and rate performance. • A strategy for developing robust MXene fibers by introducing interfacial cross-linking. • The MPG features highly aligned arrangement, larger interlayer spacing, abundant hydrogen bond and covalent bond. • The optimized MPG shows superior electrochemical behavior with high capacitance, fast rate response. • Solid-state FSCs using MP 3% G show enhanced energy density and power density.