Comment on “Flexible Asymmetric Supercapacitors Based on Nitrogen‐Doped Graphene Hydrogels with Embedded Nickel Hydroxide Nanoplates”

Abstract

It is argued that the main claims of "Flexible Asymmetric Supercapacitors Based on Nitrogen-Doped Graphene Hydrogels with Embedded Nickel Hydroxide Nanoplates" are strongly exaggerated. By selecting first a subregion (ΔV) of the total voltage drop, the capacitance (C ) is inflated by 30 %. Then, by selecting different regions for different properties and using different ΔV values in different terms of a single expression for the energy density (E ), the value is doubled. A bending angle of only 45° is instead claimed to be 180°.