Facile fabrication of ethylene glycol intercalated cobalt-nickel layered double hydroxide nanosheets supported on nickel foam as flexible binder-free electrodes for advanced electrochemical energy storage

The present work provides an alternative straight-forward process protocol to achieve a binder-free electrode material with optimal performance for the large scale fabrication and application in electrochemical energy storage. The conventional method for the preparation of electrodes, also called slurry-coating technique, suffers some difficulty in boosting the high performance and large-scale industrial fabrication of electrode materials. It becomes equally urgent to develop advanced electrode materials and to design superior electrode architectures. Here, we prepared a flexible binder-free electrode material by anchoring ethylene glycol (EG) intercalated cobalt and nickel layered double hydroxide nanosheets on Ni foam (E-Co-Ni LDH/Ni foam) via a facile effective vacuum freeze-drying technique, following a modified coprecipitation. By this way, the complex steps in the slurry-coating process were avoided and excessively aggregating of the E-Co-Ni LDH nanosheets was refrained from, which supply high accessible surface area and large number of micro/mesopores for electrochemical reaction. When directly used as a supercapacitor electrode, the E-Co-Ni LDH/Ni foam displayed a high specific capacitance of 774 F g −1 at the current density of 0.2 A g−1 with a unique cyclability at a high load mass of 3.27 mg cm−2.