Insight into the composition effect of nickel cobalt layered double hydroxide nanoarrays with the enhanced synergistic effect for supercapacitor electrode

Rational post-treatment of Ni/Co-based electrode with high mass-loading in term of the increase of surface active sites and the enhancement of the synergistic effect is facile to achieve desirable electrochemical performances for energy storage. In this work, the composition effects on the structure and capacitive performance of NiCo layered double hydroxide (NiCo LDH) nanostructured is discussed, and subsequently the structural diversity of NiCo LDH is regulated via an alkali conversion. The result suggests that bimetallic synergistic effect can be enhanced via the charge exchange during alkali conversion, resulting in gradual increase surface content of Ni3+ and Co3+ cations. Such evolution endows Ni0.60Co0.40 LDH nanoarrays with outstanding performance as a battery-type Faradaic electrode material for supercapacitor, with areal capacity of 5.15 C cm(-2) at 5 mA cm(-2), excellent rate capability and high cyclic stability. The presented work not only provides a promising electrode material for super capacitor, but also offers a new route toward understand the composition effect, bimetallic synergistic effect and the activation of Ni/Co-based electrode materials for energy storage and conversion.

Automated summary

This study discusses the composition effects on the structure and capacitive performance of NiCo layered double hydroxide (NiCo LDH) and regulates the structural diversity of NiCo LDH through alkali conversion. The results show that alkali conversion can enhance the bimetallic synergistic effect and increase the surface content of Ni3+ and Co3+ cations. This evolution enables Ni0.60Co0.40 LDH nanoarrays to exhibit excellent electrochemical performance.