MOF−Derived Core‐Shell La(OH)<sub>3</sub>@Cu(OH)<sub>2</sub>/Co(OH)<sub>2</sub> Heterostructure for Supercapacitors
Diab Khalafallah, Yunxiang Zhang, Qinfang Zhang
Abstract
Abstract Structural metal‐organic framework (MOF)‐based pseudocapacitive components have exhibited significant potential for supercapacitors. Herein, a highly functioning vertically aligned La(OH) 3 @Cu(OH) 2 /Co(OH) 2 core‐shell composite was in situ yielded from the template Co MOF‐74 frameworks on the nickel foam (Co MOF/NF) via a dual approach of heterointerfacing and structural engineering. The sacrificial template Co MOF/NF microrods were converted into binary hydroxide Cu(OH) 2 /Co(OH) 2 /NF (Cu/Co/NF) junction with spatial nanogranule self‐assembled microrods‐like structure through a cation exchange reaction. Subsequently, the binary hydroxide Cu/Co junction was employed as a backbone to stabilize La(OH) 3 species via an electrodeposition process, forming a heterostructural La(OH) 3 @Cu/Co/NF (La@Cu/Co/NF) core‐shell composite. Preliminary electrochemical analysis demonstrates the efficiency of the binder‐free La@Cu/Co/NF core‐shell electrode, revealing a specific capacitance value of 874.8 F g −1 at 1 A g −1 and high rate ability (65.2 % capacitance retention at 30 A g −1 ). Hence, it combines rich electrochemical reactive sites for Faradaic redox reactions and the favorable synergistic effect of integrated constituents. The configured La@Cu/Co/NF//AC asymmetric supercapacitor (ASC) device boasts a maximum voltage window of 1.55 V, acquiring an energy density of 43.9 Wh kg −1 at 775 W kg −1 . Besides, the device maintains a capacitance retention rate of 76.4 % even after enduring 11,000 charge‐discharge cycles, suggesting good long‐term durability.