Polyoxometalate-metal organic framework hybrid materials for electrochemical energy applications

Energy materials play a crucial role in determining the performance of electrochemical systems, with continuous advancements enhancing energy utilization efficiency and enabling a broad range of applications. In this context, significant efforts have been devoted to the development of novel materials for further improving device performance. Polyoxometalate–metal organic framework (POM-MOF) composites have emerged as a promising class of hybrid materials due to their hierarchical structures, which enhance the availability of active sites, facilitate efficient charge transfer, and improve catalytic performance and mechanical stability. This review summarizes recent advances in the rational design and modification of POM–MOF-based energy materials, highlighting key performance-enhancing strategies such as morphology tailoring, doping, defect engineering, and the incorporation of other materials (conducting polymers, transition metals, non-precious metals, etc.), as well as the underlying design principles and structure–activity relationships governing their electrochemical behavior. Their applications are particularly emphasized in electrochemical energy conversion (fuel cells, water electrolyzers, and CO2 electrolyzers) and energy storage (batteries and supercapacitors). These advancements have enabled electrochemical systems with low overpotentials (< 100 mV), high capacities (~ 1000 mAh g⁻¹), outstanding cycling stabilities (> 90%), high power densities (~ 1000 mW cm⁻²), long-term operational stability (> 5000 h), Faradaic efficiencies above 90%, and wide pH operating ranges. Further, key challenges are discussed and future perspectives are provided to guide the design of efficient POM–MOF-based electrochemical energy materials, accelerating their transition toward practical applications.