Mesoporous LaFeO3 perovskite derived from MOF gel for all-solid-state symmetric supercapacitors

Sol-gel strategies have attracted enormous attention in synthesis of perovskite-type oxides due to their excellent chemical homogeneity and possibility in controlling the size, morphology, chemical properties and texture of particles. Nevertheless, their complicated, time-consuming process and weak control over porous structure impeded their potential use in preparation of energy storage materials. Herein, a simple and rapid strategy based on MOF gel (MIL-100-Fe) is developed for fabricating mesoporous perovskite-type materials. The MOF gel can be synthesized in controllable time duration without multi complexing agent, particular pH conditions and high temperature treatment. The synthesized perovskite LaFeO 3 has mesoporous structure and the pore size is concentrated at 2 nm, which contribute to a specific capacitance of 241.3 F g −1 at 1 A g −1 with retention of 68% even at a high current density of 20 A g −1 . Meanwhile, the all-solid-state symmetric supercapacitor shows a wide potential window of 1.8 V, and an outstanding energy density of 34 W h kg −1 at a power density of 900 W kg −1 with 92.2% capacitance retention after 5000 cycles, outperforming previously reported perovskite-type electrode materials and even comparable to MOF derived iron oxides. Thus, this study opens a new way to construct porous perovskite-type electrode materials for supercapacitors, which can combine the chemical homogeneity of sol-gel technology and the porous properties of MOF template together.