Facile construction of Co(OH)2@Ni(OH)2 core-shell nanosheets on nickel foam as three dimensional free-standing electrode for supercapacitors

Abstract Fabricating three dimensional (3D) free-standing electrode is considerable attractive in designing supercapacitors of high energy and power densities. Co(OH) 2 @Ni(OH) 2 core-shell nanosheets have been successfully grown on nickel foam (NF) as 3D free-standing electrode (denoted as NCN) for electrochemical capacitors via a facile stepwise electrodeposition process. It is found that the unique 3D free-standing frameworks combined with the core-shell nanosheet-like heterostructure endow the as-prepared electrode good electrochemical performances. When tested as a supercapacitor electrode, it delivers a capacitance of 1520.6 F g −1 at 1 A g −1 and still keeps 1376.6 F g −1 at 10 A g −1 , exhibiting excellent rate performance. Moreover, it retains ∼71.4% initial capacitance after 1500 charging/discharging cycles at 5 A g −1 , demonstrating good cycling stability. The good electrochemical performance of the NCN electrode makes it a promising electrode candidate for high performance supercapacitors.