Compressed Nanolamella‐Stacked Ni(OH)₂/NiCo₂O₄ Composite as Electrode for Battery‐Type Supercapacitor

Abstract

Transition metal oxides/hydroxides as electrode materials for supercapacitors have drawn great attention in the past decades. However, the large volume expansion during the cycling always leads to capacity decrease and short cycle life. In this paper, a compressed Ni(OH)2/NiCo2O4 nanolamellas composite grown on nickel foam is synthesized by a one‐step hydrothermal method towards the enhanced performance of supercapacitors. The resulting Ni(OH)2/NiCo2O4 composite displays unexpectedly excellent cycle stability both in single‐electrode cycling (112 % after 90,000 cycles at 5 mA cm−2) and hybrid supercapacitor cycling (124 % after 80,000 cycles at 1 A g−1). The excellent electrochemical performances are attributed to the unique compressed nanolamella‐stacked architecture, which can not only accommodate the volume expansion, but also increase the contact area between the electrode and electrolyte.

Facile High Throughput Wet-Chemical Synthesis Approach Using a Microfluidic-Based Composition and Temperature Controlling Platform

“…Among the existing methods of chemical synthesis, the wet-chemical technique has been widely applied due to its versatility and flexibility (Yoshimura and Byrappa, 2008 ; Danks et al, 2016 ). The wet-chemical technique can be used to prepare numerous materials, ranging from structural materials such as ceramics (Sato, 2010 ; Palmero, 2015 ; Huang et al, 2017 ) and alloys (Dong et al, 2017 ; Wang et al, 2019 ), to functional materials such as energy materials (Ye et al, 2018 ; Chen et al, 2019 ; Guo et al, 2020 ; Song et al, 2020 ; Wu et al, 2020 ), optical materials (Rachna, 2013 ; Wang et al, 2017 ; Li et al, 2018 ), magnetic materials (Nakahara et al, 2010 ; Chen et al, 2013 ; Yang et al, 2017 ), and catalytic materials (Zhong et al, 2014 ; Qu et al, 2016 ; Ding et al, 2019 , 2020 ). Researchers have put great effort into tuning the wet-chemical synthesis parameters like reagent concentration, temperature, reaction time, acidity (or pH) toward optimal reaction conditions for desirable product morphology, and characteristics (Huang et al, 2012 ; Jean et al, 2012 ; Zheng et al, 2018 ; Xu et al, 2019 ; Yan et al, 2020 ).…”