Synthesis of high-performance nickel hydroxide nanosheets/gadolinium doped-α-MnO2 composite nanorods as cathode and Fe3O4/GO nanospheres as anode for an all-solid-state asymmetric supercapacitor

GdMnO 2 /Ni(OH) 2 composite nanorods and Fe 3 O 4 /GO was synthesized and used as electrode material for all-solid-state supercapacitor, which exhibited superior capacitance and energy density. The wide use of manganese dioxide (MnO 2 ) as an electrode in all-solid-state asymmetric supercapacitors (ASCs) remains challenging because of its low electrical conductivity. This complication can be circumvented by introducing trivalent gadolinium (Gd) ions into the MnO 2 . Herein, we describe the successful hydrothermal synthesis of crystalline Gd-doped MnO 2 nanorods with Ni(OH) 2 nanosheets as cathode, which we combined with Fe 3 O 4 /GO nanospheres as anode for all-solid-state ASCs. Electrochemical tests demonstrate that Gd doping significantly affected the electrochemical activities of the MnO 2 , which was further enhanced by introducing Ni(OH) 2 . The GdMnO 2 /Ni(OH) 2 electrode offers sufficient surface electrochemical activity and exhibits excellent specific capacity of 121.8 mA h g −1 at 1 A g −1 , appealing rate performance, and ultralong lifetime stability (99.3% retention after 10,000 discharge tests). Furthermore, the GdMnO 2 /Ni(OH) 2 //PVA/KOH//Fe 3 O 4 /GO solid-state ASC device offers an impressive specific energy density (60.25 W h kg −1 ) at a high power density (2332 W kg −1 ). This investigation thus shows its large potential in developing novel approaches to energy storage devices.