Preparation of Sea Urchin‐Like Co/Ni Alloy Compounds for Pseudocapacitive Supercapacitor

Energy density and power density are the two most crucial metrics in advanced electrochemical energy storage (EES) devices. The design of pseudocapacitor materials with good structure and reasonable composition can ensure that the power density can be greatly increased under the condition of little or no reduction in energy density. However, how to reasonably design excellent pseudocapacitor materials is still a huge challenge. Herein, layered double hydroxides containing Ni and Co elements on carbon materials derived from distillers’ grains by hydrothermal synthesis (NiCo‐LDH/JKPC‐2) are grown. The fabricated NiCo‐LDH/JKPC‐2 has exhibited a sea urchin‐like nanostructure that primarily consists of mesoporous and possesses a high specific surface area (303 m 2 g −1 ), which facilitates the formation of larger active sites, thereby increasing the rate of charge transport. The specific capacitance of the NiCo‐LDH/JKPC‐2 reaches a maximum value of 1454 F g −1 at 1 A g −1 . When it combines with carbon materials originating from distillers’ grains, the assembled asymmetric supercapacitor electrode exhibits a remarkable energy density (40.86 Wh kg −1 at 775 W kg −1 ) and superior power density (7750.8 W kg −1 at 21.53 Wh kg −1 ). Thus, the NiCo‐LDH/JKPC‐2 asymmetric supercapacitor electrode can be considered as a potential candidate in advanced energy storage device systems.