B-site regulated bimetallic perovskite fluoride NaCo1-xNixF3/reduced graphene oxide as the enhanced performance electrode material for supercapacitors

Perovskite fluoride is a potential electrode material for supercapacitors because its high theoretical specific capacitance. However, the relatively poor cyclic stability and rate performance limit its practical application. In this paper, we successfully synthesized the bimetallic perovskite fluorides/reduced graphene oxide (NaCo0.2Ni0.8F3/rGO) composite materials through a simple solvothermal method. The effects of the Co/Ni ratio regulation and the addition of rGO on the electrochemical properties of the perovskite composite materials have been investigated in detail. The variable valence metal ions by Co/Ni ratio regulation can lead to multiple redox reactions, which are helpful to improve the specific capacity of the materials. Meanwhile, the addition of rGO could improve the cycle stability and rate performance by virtue of the great conductivity of the rGO and the uniform dispersion of perovskite nanoparticles on it. The NaCo0.2Ni0.8F3/rGO composite electrode displays the high specific capacity of 805.7 C g(-1), excellent rate performance (82% capacity retention from 0.5 to 16 A g(-1)) and superior cycle stability (92% retention over 5000 cycles). Furthermore, the active carbon//NaCo0.2Ni0.8F3/rGO asymmetric supercapacitor exhibits a high energy density of 52.19 Wh kg(-1) under a power density of 750 W kg(-1). It is believed that the above findings supply an efficient electrode design for the future practical application of perovskite fluorides in high-performance supercapacitor. (c) 2022 Elsevier B.V. All rights reserved.