Title: In Situ Synthesis of Vertical Standing Nanosized NiO Encapsulated in Graphene as Electrodes for High‐Performance Supercapacitors

Abstract: NiO is a promising electrode material for supercapacitors. Herein, the novel vertically standing nanosized NiO encapsulated in graphene layers (G@NiO) are rationally designed and synthesized as nanosheet arrays. This unique vertical standing structure of G@NiO nanosheet arrays can enlarge the accessible surface area with electrolytes, and has the benefits of short ion diffusion path and good charge transport. Further, an interconnected graphene conductive network acts as binder to encapsulate the nanosized NiO particles as core–shell structure, which can promote the charge transport and maintain the structural stability. Consequently, the optimized G@NiO hybrid electrodes exhibit a remarkably enhanced specific capacity up to 1073 C g⁻¹ and excellent cycling stability. This study provides a facial strategy to design and construct high‐performance metal oxides for energy storage.