Cation\nVacancy Strategy Activated Layered Double Hydroxides:\nEnhanced Electrochemical Performance and Longevity

The defect design strategy has been\nextensively employed to enhance\nthe reaction kinetics of layered double hydroxide (LDH) electrode\nmaterials. Furthermore, it is anticipated to improve the cyclic stability\nof LDHs through this approach, serving a dual purpose. However, the\npotential mechanisms of cation vacancies’ impact on the electrochemical\nperformance of electrodes at the atomic scale still need further clarification.\nIn this study, a typical aluminum-vacancy LDH material via a simple\nalkaline etching method was demonstrated. Electrochemical in situ\nRaman spectroscopy, ex situ X-ray diffraction (XRD), and first-principles\ncalculations were utilized to elucidate the mechanism of Faradaic\nreactions. The findings indicate that this cation vacancy strategy\nnot only enhances the electrochemical reaction kinetics of the electrodes\nbut also effectively reduces the energy barrier for the α to\nγ phase transition of LDHs during the charge–discharge\nprocesses, thereby enhancing its longevity. To further validate the\npractical application of this defect design, an asymmetric solid-state\nsupercapacitor was formed, which maintains 93.9% capacity after 20 000\ncharge–discharge cycles. This research offers technical guidance\nfor the development of a new generation of high-performance and long-life\nLDH electrode materials based on a cation vacancy strategy.