Engineering oxygen vacancies into ZnCo hydrotalcite for boosting performances for flexible supercapacitor

ZnCo layered double hydroxide grown on carbon cloth (O v -LDH) with rich oxygen vacancies was rationally designed and synthesized via a facile one-step hydrothermal process, which exhibited a benign electrochemical property . The existing oxygen vacancies provided enriched active sites, which enhanced the electrical conductivity and accelerated the redox reactions . Density functional theory (DFT) calculations substantiated that oxygen vacancies tuned the electronic structure and reduced OH − adsorption energy , which effectively facilitated ion accessibility and transmission. The optimal O v -LDH (3) offered a high specific charge of 798.9 C g −1 at 1 A g −1 with an extraordinary cycling stability. Furthermore, the corresponding hybrid supercapacitor (O v -LDH//AC) delivered a satisfactory energy density (57.9 Wh kg −1 at 849.4 W kg −1 ) and a long lifespan (93.2 % retention at 5 A g −1 after 10 000 cycles). This work provided a feasible strategy for developing high-performance LDH-based electrode materials in energy storage. • Oxygen vacancy-rich ZnCo-LDH was synthesized using 2-methylimidazole. • Oxygen vacancies offered enriched active site. • The optimal O v -LDH exhibited excellent electrochemical performances. • The assembled O v -LDH//AC device showed broaden potential in energy storage field.