Design of high-mass loading metal–organic framework-based electrode materials with excellent redox activity for long-lasting electrochemical energy storage applications.

Via a simple and cost-effective one-pot solvothermal synthesis, the highly conductive metal–organic framework-derived binder-free electroactive materials deliver excellent redox reactions and outstanding cycling performance. The optimized electrode is used as the positive electrode to fabricate the electrochemical cell and it exhibits excellent electrochemical properties and cycling stability. [Display omitted] • Ni-Co TH with commercial-level mass loading was prepared by a simple solvothermal method. • The effect of reaction time and temperature on the morphology and electrochemical properties was investigated. • All the prepared Ni-Co TH electrodes revealed ultrahigh areal capacity. • The obtained micro- and nano-structures for optimum electrode showed superior areal capacity. • The fabricated electrochemical cell exhibited outstanding cycling stability. Nowadays, metal–organic framework-derived (MOF-D) materials are auspicious in various research areas due to their beneficial traits of diverse structural features, large surface area, and high porous nature. Herein, we report the MOF-D nickel–cobalt terephthalate hydroxides (Ni-Co THs) via a one-pot solvothermal approach without further annealing. Direct growth of active materials on conductive substrates (e.g., nickel foam (NF)) can potentially eliminate the use of sluggish and non-conductive binders, leading to enhanced redox chemistry with commercial-level mass loading (8–10 mg cm−2). All the binder-free MOF-D Ni-Co TH electrodes demonstrated excellent areal capacities at the same current density of 3 mA cm−2. Among them, the Ni-Co TH-160/9h electrode delivered a superior areal capacity/specific capacity of 2087 µAh cm−2/200.68 mAh g−1 at 3 mA cm−2, together with outstanding cycling retention of 100 % after 20,000 charge–discharge cycles. The achieved ultrahigh performance is ascribed to the synergistic properties of Ni-Co THs, three-dimensional porous NF, and morphological structures. Utilizing the charge storage performance of the Ni-Co TH-160/9h electrode, an electrochemical cell (ECC) was assembled. The as-assembled ECC delivered good areal capacity (1678.6 µAh cm−2), energy density (1.3 mWh cm−2), and power density (48.6 mW cm−2) with outstanding cycling performance (35,000 cycles (99.9 %)). Also, the ECC verified its energy storage properties by powering various portable electronic appliances. [ABSTRACT FROM AUTHOR]