Towards 3D knitted-fabric derived supercapacitors with full structural and functional integrity of fiber and electroactive materials

Abstract

Truly knitted textiles based supercapacitors (SCs) are receiving great attention owing to their inherent flexibility and electrochemical performance. Here, the one-pot knitted conductive 3D spacer fabric (3DSF) was, for the first time, used as the frame supporting the highly pseudocapacitive materials. MnO2 and the electrochemically reduced graphene oxide (ErGO) are grown on the top and bottom layer of the 3DSF respectively, realizing a 3D all-textile asymmetric SC (3DAS) with a functional and structural integrity. Both water-proof and wear-resistant properties are readily rendered after encapsulating with the flexible multifunctional polyurethane (PU) film. A high specific capacitance of 1.02 F cm−2 (36.59 F g−1) is achieved at the current density of 7.5 mA cm−2 (0.275 A g−1), and the maximum areal energy density is nearly 1.02 mWh·cm−2 at a power density of 5.27 mW cm−2. The approach of coupling the advanced computerized technology with the chemical synthesis opens new avenues for the development of the truly flexible and wearable energy storage devices.