In-situ growth transformation and oxygen vacancy synergistic modulation of the electronic structure of NiCo-LDH enables high-performance hybrid supercapacitors

This article successfully constructs NiCo-LDH nano cages formed by in-situ triggering (IS-LDH), and synergistically modulates the electronic structure by introducing oxygen vacancies. The in-situ triggered generation of NiCo-LDH (IS-LDH) by synthesizing ZIF-67 owns a typical rhombic dodecahedral structure and sensitivity to acid etching. Characterization analysis revealed that the IS-LDH nanocage succeeded the polyhedral structure morphology of ZIF-67 but with multiple vertically aligned nanosheets on the shell. Oxygen vacancies (Ov) were introduced into the IS-LDH through a chemical reduction process using sodium borohydride. The findings demonstrate that the synthesized OvIS-LDH nanocapacitor has a low charge transfer resistance (Rct) with a specific capacitance as high as 1111C g−1 (at 1 A g−1). After 10,000 cycles of charge-discharge measurements, the capacity retention rate was 89.45%. Density functional theory (DFT) calculations confirmed that the inclusion of Ov enhanced the repulsion of OH− by the LDH nanosheets and improved the intrinsic conductivity of LDH. The assembled hybrid supercapacitor (OvIS-LDH//AC) successfully powered an LED light for 20 min. This study proposes a logical approach for developing anode materials that can enhance the performance of supercapacitors.