3D Wearable Fabric‐Based Micro‐Supercapacitors with Ultra‐High Areal Capacitance

Abstract Miniaturized electronics require integrated unit configuration in very limited space, where energy storage per unit area is thus extremely critical. Micro‐supercapacitors (MSCs), mainly established on planar substrates, are superior but still suffer from limited areal capacitance. Herein, a novel strategy is introduced to construct high cross‐section MSCs using 3D fabrics as the porous skeleton. Interdigitated poly(3,4‐ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) is patterned on 3D fabrics to achieve continuous conductive networks, while MnO 2 microspheres epitaxially grown on PEDOT:PSS are fully exposed to electrolyte with the support of fabric fibers. The unique architecture can utilize more active sites of thick electrodes and the high conductivity of interpenetrating fiber networks. The resulting fabric‐based MSCs demonstrate ultra‐high areal capacitance of 135.4 mF cm −2 , which is 3.5 times that of devices on polyethylene terephthalate substrates and is among the highest values for planar‐based MSCs using the same interdigital geometry. Moreover, the flexible fabrics endow MSCs with extremely high bending stability with 94% capacitance retention even after 3000 cycles. These figures‐of‐merit enable fabric‐based MSCs promising to be used in the next‐generation of wearable electronics.