Flash Joule Heating: A Transformative Non‐Equilibrium Strategy for Next‐Generation Advanced Materials

High-temperature synthesis methods play a pivotal role in the development of advanced functional materials. However, conventional approaches often suffer from high energy consumption, prolonged reaction durations, and limited control over metastable phase formation. Flash Joule heating (FJH), an electrothermally driven transient energy conversion technique, applies short-duration (<10s), high-intensity electrical pulses (>2000 W) to achieve ultrafast heating and cooling (typically >10²-10⁵ K s^-1), with peak temperatures reaching up to 3,500 °C, and energy utilization efficiency is close to 100%. This non-equilibrium thermodynamic environment facilitates the rapid transformation of diverse precursors into carbon-based and inorganic materials, enabling highly tunable compositions, multiscale architectures, and abundant defect states. As such, FJH provides a sustainable and scalable platform for advanced materials manufacturing, while also demonstrating significant potential in waste valorization and environmental remediation. This review systematically outlines the fundamental principles and reactor configurations of FJH, elucidates the intrinsic mechanisms underlying structure reconstruction during processing, highlights the technological advantages in various application scenarios, and discusses the key challenges that must be addressed for FJH to become a central strategy in advanced materials engineering and sustainable technology development.