ContinuousFabricationofTi3C2TxMXene-BasedBraidedCoaxialZinc-IonHybridSupercapacitorswithImprovedPerformance

Zinc-ion hybrid fiber supercapacitors（FSCs） are promising energy storages for wearable electronics owing to their high energy density,good flexibility,and weavability.However,it is still a critical challenge to optimize the structure of the designed FSC to improve energy density and realize the continuous fabrication of super-long FSCs.Herein,we propose a braided coaxial zinc-ion hybrid FSC with several meters of Ti3C2Tx MXene cathode as core electrodes,and shell zinc fiber anode was braided on the surface of the Ti3C2Tx MXene fibers across the solid electrolytes.According to the simulated results using ANSYS Maxwell software,the braided structures revealed a higher capacitance compared to the spring-like structures.The resulting FSCs exhibited a high areal capacitance of 214 mF cm-2,the energy density of 42.8 μWh cm-2 at 5 mV s-1,and excellent cycling stability with 83.58% capacity retention after 5000 cycles.The coaxial FSC was tied several kinds of knots,proving a shape-controllable fiber energy storage.Furthermore,the knitted FSC showed superior stability and weavability,which can be woven into watch belts or embedded into textiles to power smart watches and LED arrays for a few days.