Sulfide‐Based Nickel‐Plated Fabrics for Foldable Quasi‐Solid‐State Supercapacitors

Smart wearable market is burgeoning, and flexible energy storage is crucial to cope with its development. The commonly‐used metal‐based current collectors are heavy with limited flexibility. Other carbon‐based current collectors are expensive and fragile. Moreover, the poor interface between active material and current collector leads to unsatisfactory stability. Herein, these two issues are attempted to be solved by using cheap and lightweight polyester‐based fabrics as well as in‐situ growth. A deposited thin layer of nickel on the fabrics not only enhances the conductivity, but also serves as the sacrificial precursor for the growth of active materials. Thus, intimate contact is secured via chemical bonding. The electrode with ternary (metal‐inorganic‐organic) component shows excellent electrochemical performance. Namely, high areal capacity is realized (2.2 C cm −2 at 2 mA cm −2 ), which is far superior to its rigid nickel‐foam‐based counterpart. Furthermore, an all‐solid‐state supercapacitor device was assembled. The device provides an areal capacity of 2.03 C cm −2 at the current density of 2 mA cm −2 . It realizes an energy density of 0.45 mWh cm −2 when the power density is 1.6 mW cm −2 . This work offers a feasible and cost‐efficient way for fabricating electrode materials with excellent performance for portable supercapacitors.