Abstract

Oxygen vacancies (VOs), as functional defects in the lattice, offer significant benefits such as enhanced electrical conductivity, improved ion transport, and elevated redox activity. These advantages contribute to the improvement of key performance parameters relevant to charge storage, making VOs essential for the development of advanced supercapacitor materials. This review examines the synergistic integration of microwave-assisted synthesis (MAS) with X-ray techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS), to probe the formation of VOs in supercapacitor electrode materials. Synthesis by MAS enables the precise engineering of VOs through rapid, uniform heating, thereby producing electrode materials with tailored defect concentrations. Complementary X-ray techniques comprehensively characterize these properties. These tailored VOs are shown to significantly enhance the electrochemical performance of supercapacitor electrode materials, including improved specific capacitance, rate capability, and cycling stability. The main focus of this review is on recent advances in understanding VOs formation mechanisms, MAS parameters, and multi-technique X-ray characterization protocols. By integrating MAS with systematic X-ray characterization, this work establishes a coherent framework for the rational design of next-generation supercapacitor electrode materials with superior electrochemical performance.