Benzoic acid-modified 2D Ni-MOF for high-performance supercapacitors.

• The morphology and electronic structure of NiMOF are regulated by the replacement of terephthalic acid with benzoic acid. • Benzoic acid-modified 2D Ni-MOF electrodes have a high capacitance of 2.38 c cm−2 at 1 mA cm−2. • The hybrid supercapacitor showed a high energy density of 50.1 Wh kg−1 at the power density of 2550 W kg−1. • The capacitance retention of benzoic acid-modified 2D Ni-MOF electrode is 88% after 10,000 cycles. Designing metal-organic frameworks (MOFs) with large specific surface area, high conductivity and abundant active sites are highly desirable for high-performance supercapacitors. Herein, the microstructure and electronic structure of NiMOF nanosheets were regulated by the partial substitution of dicarboxylic terephthalic acid (PTA) with monocarboxylic benzoic acid (BA), leading to high electronic conductivity and abundant electroactive sites of MOFs. The prepared NiMOF-10 nanosheets with 10 mol% BA substituting PTA exhibit the excellent electrochemical performance with a high specific capacity of 2.38 C cm−2 at 1 mA cm−2, and outstanding cycling stability (88% after 10,000 cycles). The fabricated hybrid supercapacitor (HSCs) demonstrated the maximum energy density of 50.1 Wh kg−1 at a power density of up to 2550 W kg−1. The exceptional electrochemical performance of NiMOF nanosheets is assigned to the improved electronic conductivity and abundant active sites induced by ligand exchange. [Display omitted] [ABSTRACT FROM AUTHOR]