High-performance Ni–Gd@BTC MOF electrodes enable enhanced Energy storage in aqueous asymmetric supercapacitors

Abstract Metal–organic frameworks (MOFs) have emerged as promising electrode materials for next-generation supercapacitors owing to their high density of redox-active sites and tunable architectures. Here, we report the hydrothermal synthesis of a bimetallic Ni–Gd@BTC MOF and evaluate its electrochemical energy-storage performance. The resulting material exhibits a layered, sheet- like morphology that promotes rapid ion transport and efficient charge-transfer kinetics. When employed as an electrode in a three-electrode configuration, Ni–Gd@BTC delivers a high specific capacitance of 910.98 F g⁻¹ at 0.7 A g -1 , underscoring its strong charge-storage capability. The electrode also demonstrates excellent long-term durability, retaining 88% of its initial capacitance with 98% Coulombic efficiency after 10,000 charge–discharge cycles at 5 A g -1 . To assess device-level performance, we assembled a battery-type asymmetric supercapacitor (Ni–Gd@BTC MOF//AC). The device achieves an energy density of 43.11 Wh kg -1 and a power density of 3200 W kg -1 at 1 A g -1 , along with 90 % capacitance retention after 10,000 cycles at 5 A g -1 . Collectively, these results establish Ni–Gd@BTC MOF as a highly effective electrode material with substantial potential for high-performance electrochemical energy-storage systems.