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 /NiCo 2 O 4 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 /NiCo 2 O 4 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.