Wearable High‐Performance Supercapacitors Based on Silver‐Sputtered Textiles with FeCo2S4–NiCo2S4 Composite Nanotube‐Built Multitripod Architectures as Advanced Flexible Electrodes

To achieve high‐performance wearable supercapacitors (SCs), a new class of flexible electrodes with favorable architectures allowing large porosity, high conductivity, and good mechanical stability is strongly needed. Here, this study reports the rational design and fabrication of a novel flexible electrode with nanotube‐built multitripod architectures of ternary metal sulfides' composites (FeCo 2 S 4 –NiCo 2 S 4 ) on a silver‐sputtered textile cloth. Silver sputtering is applicable to almost all kinds of textiles, and S 2− concentration is optimized during sulfidation process to achieve such architectures and also a complete sulfidation assuring high conductivity. New insights into concentration‐dependent sulfidation mechanism are proposed. The additive‐free FeCo 2 S 4 –NiCo 2 S 4 electrode shows a high specific capacitance of 1519 F g −1 at 5 mA cm −2 and superior rate capability (85.1% capacitance retention at 40 mA cm −2 ). All‐solid‐state SCs employing these advanced electrodes deliver high energy density of 46 W h kg −1 at 1070 W kg −1 as well as achieve remarkable cycling stability retaining 92% of initial capacitance after 3000 cycles at 10 mA cm −2 , and outstanding reliability with no capacitance degradation under large twisting. These are attributed to the components' synergy assuring rich redox reactions, high conductivity as well as highly porous but robust architectures. An almost linear increase in capacitance with devices' area indicates possibility to meet various energy output requirements. This work provides a general, low‐cost route to wearable power sources.