Ordered Interface Engineering Enabled High-Performance Ti₃C₂T_xMXene Fiber-Based Supercapacitors

The advanced design of heterostructured fibers with ordered transport channels and porous frameworks for high-speed ions/electrons kinetics is principally fundamental for high-performance fiber-based supercapacitors (FSCs). However, typically low energy-storage performances restrict their substantive applications due to a fibrous restacking phenomenon and poor interfacial charge transfer. Here, we develop an ordered core-shell fiber, wherein the porous zeolitic imidazolate framework-67 (ZIF-67) polyhedron shell is uniformly loaded on a highly conductive Ti3C2Tx core via a versatile microfluidic method. Due to the improved porous generation, ordered porous pathways, large exposed surface, and in situ interfacial electron transfer, the ZIF-67@Ti3C2Tx fiber displays excellent volumetric capacitance (972 F cm-3) and long-term cycling stability (90.8% capacitive retention after 20 »000 cycles) in 1 M KOH electrolytes. Meanwhile, the flexible solid-state ZIF-67@Ti3C2Tx FSCs maintain a good capacitance, large bending/wearable stabilities, and steady temperature-dependent capability. Based on those significant electrochemical performances, the supercapacitors can impressively power various electrical devices [e.g., light-emitting diodes (LEDs), displays, electric fans, pinwheels, and rolling bells], which will guide the practical progress of miniaturized energy technologies and smart electronics.