CeO2/Ni-Al layered double hydroxide composite electrode for the enhancement of specific capacitance and capacitance retention performance

Abstract

Layered double hydroxides(LDH) possessed excellent capacitive properties but with poor cycling performance and low specific capacitance at high current density. CeO2/Ni-Al LDH (NAHCe) composite was synthesized by a one-step hydrothermal method to improve the electrochemical performance Ni-Al LDH. The scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) results proved the well distribution of cerium on the surface of the Ni-Al LDH laminate structure. The specific capacitance and capacitance retention after 1000 cycles of the optimal composite NAHCe-2.5 reached 879.63 F·g−1 at 1 A g−1 and 90.36% at 2 A g−1, which was higher than that of NAH (541.82 F·g−1 at 1 A·g−1, 62.9% at 2 A·g−1 after 1000 cycles) under the same conditions. The CeO2 particles loaded on Ni-Al LDH sheets effectively reduce the internal electrochemical resistance of the composite electrode which contributed to the improvement of the specific capacitance and capacitance retention performance of the electrode. The idea of CeO2/LDH composite for the enhancement of electrochemical performance could be of help for the synthesis of other new-type supercapacitors.