Layer by layer inkjet printing reduced graphene oxide film supported nickel cobalt layered double hydroxide as a binder-free electrode for supercapacitors

In our works, the reduced graphene oxide (rGO) ink was prepared successfully. Then, the thin rGO film was fabricated by using inkjet printing method, which can act as a high-conductive supporter for anchoring more active materials. Hence, the Ni-Co LDH as a main active material was applied to enhance the electrochemical activity via one-step electrochemical deposition method. To further meet practice application, the electrochemical performances and mass loading of electroactive material were improved by repeating inkjet printing and electrochemical deposition method. The capacity of Ni-Co LDH/rGO/Ni-Co LDH/rGO is reached to 227 mAh g(-1) at 1.2 A g(-1), and the capacity value can remain 78.7% after charge-discharge 5000 cycles. The two-electrode supercapacitors were fabricated from the Ni-Co LDH/rGO/Ni-Co LDH/rGO as positive electrode and commercial active carbon as negative electrode. The improvements of electrochemical properties of Ni-Co LDH/rGO/Ni-Co LDH/rGO//AC can be achieved in energy density of 84.9 Wh kg(-1) and power density of 424 kW kg(-1).