Construction of nanowall-supported-nanorod nico ldh array electrode with high mass-loading on carbon cloth for high-performance asymmetric supercapacitors

Abstract

Carbon cloth is regarded as a promising substrate for supercapacitors due to its good electrical conductivity, light weight and flexibility. However, its relatively hydrophobic property prevents the large-scale growth of active substances, restricting the potential practical applications. In this paper, by using NiCo LDH nanowall array as a hydrophilic substrate, a high mass-loading nanowall-supported-nanorod NiCo LDH arrays are formed via an alternate solvo/hydrothermal synthesis and subsequently alkali conversion process. The strong substrate adhesion of NiCo LDH nanoarrays ensures efficient electron transfer of the electrode. Moreover, the as-achieved open holey framework, integrated by free-standing nanorods and porous nanowalls, provides a hierarchical nanostructure for realizing the enhanced capacitive performance. Consequently, nanowall-supported-nanorod NiCo LDH electrode achieves a high capacitance of 7.73 F cm−2 at a current density of 5 mA cm−2 with excellent rate performance. When assembled into an all-solid-state hybrid supercapacitor, it delivers a maximum working voltage of 1.8 V, and an energy density of 0.46 mWh cm−2 (6.37 mWh cm−3) at a power density of 4.5 mW cm−2 (62.5 mW cm−2). Therefore, this work provides a proof-of-concept design for the high-performance supercapacitor electrode with carbon cloth substrate.