PEDOT coating boosted NiCo-LDH nanocage on CC enable high-rate and durable pseudocapacitance reaction

Layered double hydroxide (LDH) is supposed to be ideal capacitive materials owing to its excellent theoretical specific capacitance. Nevertheless, the inherent defects of LDH such as unstable structure, and agglomerations along with poor conductivity, lead to low rate-capability and poor cycle stability. In this work, poly(3,4-ethylenedioxythiophene) (PEDOT)@nickel-cobalt LDH on carbon cloth (PEDOT@NiCo-LDH/CC) was pro-posed as a highly capacity electrode material for supercapacitors. Herein, hollow NiCo-LDH nanocage was firstly assembled by NiCo-LDH nanosheets on CC (NiCo-LDH/CC) via an in-situ transformations of ZIF-67, sub-sequent by coating PEDOT network (PEDOT@NiCo-LDH/CC) on NiCo-LDH/CC via an electrodeposition pro-cess. The unique hollow nanocage structure can effectively restrain agglomeration of the LDH nanosheets. Besides, the introduction of PEDOT not only remarkable improves the conductivity, but also protects those hol-low LDH nanocages from destruction during the cycling process. Consequently, the PEDOT@NiCo-LDH/CC electrode manifests outstanding capacitance properties of 1508F/g at 1 A/g, excellent rate capability of 71.9 % capacitance retention in 1-20 A/g, and remarkable cycling life of 90.1 % capacity retention at 20 A/g after 10,000 cycles. Moreover, a hybrid asymmetric supercapacitor (ASC) device was assembled by using PEDOT@NiCo-LDH/CC// activated carbon. Such ASC reveals a prominent energy density of 77.1 Wh kg-1 under the power density of 750 W kg-1. This project provides new inspirations into the rational design of high-performance electrode material in application of energy storage.

Automated summary

In this work, a novel PEDOT@NiCo-LDH/CC electrode material with excellent rate capability and cycle stability was proposed. The unique hollow nanocage structure effectively restrained the agglomeration of LDH nanosheets, and the introduction of PEDOT significantly improved the conductivity and protected the hollow LDH nanocages during cycling process. Moreover, a hybrid ASC device assembled by PEDOT@NiCo-LDH/CC//activated carbon exhibited a high energy density and power density.