Hierarchical Nico Layered Double Hydroxidesnanosheets on Carbonized CNT/Cotton As a Highperformance Flexible Supercapacitor

Flexible electrodes, unlike the traditional ones, are highly integrated and portable, have attracted great attention in modern electronics fields. They can be served as essential parts in flexible supercapacitors and are critical items in the energy storage system for intelligent electronic products and health monitoring system. The core criteria to design a qualified flexible supercapacitor are high flexibility, stability and capacitance. Cotton fabric is a good choice owing to the properties like low price, easily available and hydrophilicity, in which the hydroxyl groups make it favorable for adsorbing water and reacting with active materials. Carbon nanotubes (CNT) are widely used electrode materials with the merits of high specific surface area, good chemical stability, low resistance, thermal stability, high flexibility and excellent electrical properties. However, it is hard to obtain ideal properties only combining carbon nanotubes with cotton, because the low capacity of carbon nanomaterials. Layered double hydroxides (LDHs) are promising Faradaic materials for the construction of high-performance supercapacitors, due to their unique two-dimensional lamellar structures and remarkable stability. Herein, hierarchical porous NiCo LDHs integrated with flexible CNT/cotton fabric current collector, are realized by a facile method, which exhibits a high capacitance. Moreover, the hybrid electrode has been assembled into a flexible supercapacitor device with the cycling stability of 94% capacitance retention after 3000 cycles. The better flexibility and conductivity of the CNT, and highly intrinsic electrochemical activity of the NiCo LDHs as well as the superiority of the interwoven structure are responsible for the outstanding performance of the supercapacitor. The elaborate structural design can provide new insights into the construction of high-performance flexible supercapacitors. Figure 1