Flower-like Y-doped α-Ni(OH)2/graphene heterostructure as advanced electrodes for high performance supercapacitor

Abstract To achieve high electrochemical performance, Ni hydroxide electrode materials need enhancing its intrinsic poor conductivity and fully utilizing their electroactive sites. Herein, we fabricate yttrium (Y) doped Ni(OH)2/graphene nanosheets heterostructure (Y-Ni/GNS) via a solvothermal method. The flower-like Y-Ni/GNS microspheres consist of numerous wrinkled nanoflakes and transparent graphene nanosheets, which provide increased surface areas, excellent electrical conductivity and abundant reaction sites. The Y-Ni/GNS heterostructure exhibits a remarkable specific capacity of 822.3 C g−1 at 1 A g−1, and ultrahigh rate performance (562.4 C g−1 at 20 A g−1). The as-fabricated Y-Ni/GNS//AC device delivers an energy density of 81.6 Wh kg−1 at 1129.8 W kg−1 and ultra-long cycling life, with 83.28% retention after 7000 cycles.