Ultrafast micro/nano-manufacturing of metastable materials for energy Xiaoya Cui, Yanchang Liu, and Yanan Chen Abstract: The structural engineering of metastable nanomaterials with abundant defects has attracted much attention in energy-related fields. The high-temperature shock (HTS) technique, as a rapidly developing and advanced synthesis strategy, offers significant potential for the rational design and fabrication of high-quality nanocatalysts in an ultrafast, scalable, controllable and eco-friendly way. This review provides an overview of various metastable micro- and nanomaterials synthesized via HTS, including single metallic and bimetallic nanostructures, high entropy alloys, metal compounds (e.g. metal oxides) and carbon nanomaterials. HTS provides a new research dimension for nanostructures, i.e. kinetic modulation. We summarize the application of HTS—as supporting films for transmission electron microscopy grids—in the structural engineering of 2D materials, which is vital for the direct imaging of metastable materials. Finally, we discuss the potential future applications of high-throughput and liquid-phase HTS strategies for non-equilibrium micro/nano-manufacturing beyond energy-related fields. It is believed that this emerging research field will bring new opportunities to the development of nanoscience and nanotechnology in both fundamental and practical aspects. Keywords: high-temperature shock technique, defect engineering, metastable phase, kinetic modulation, non-equilibrium micro/nano-manufacturing Introduction: Increasing concerns regarding global warming, environmental pollution and the energy crisis have prompted extensive exploration of sustainable energy strategies. However, economic growth decouples both energy consumption and CO₂ emissions. Full decarbonization and a carbon-neutral society with an effective and environmentally friendly energy system remains a great challenge. For instance, fuel cells, as a promising energy-storage system, have unique properties such as safety, eco-friendliness and superior activity. However, the stability of fuel cells still needs to be improved, especially at high currents. This improvement would be of great significance for industrial applications. The manufacturing process for micro- and nanocatalysts has encountered great obstacles, such as high surface tension, particle agglomeration, poor activity and stability, complicated fabrication, low producing efficiency, high cost and limited intrinsic structures. Therefore, great effort should be devoted to developing effective, cost-efficient and compelling strategies to synthesize stable and high-performing novel functional materials with unique structures and properties, such as metastable materials and amorphous or heterophase nanostructures, for advancing renewable energy storage and alleviating global warming. Metastable nanomaterials with abundant defects, including high entropy alloys (HEAs), show great potential in catalytic procedures with high performance and stability, since the electronic structure is strongly associated with the crystal configuration. Taking HEAs as an example, the main physical parameters contributing to the metastability include: (i) Complex composition. HEAs haveUltrafast micro/nano-manufacturing of metastable materials for energy Xiaoya Cui, Yanchang Liu, and Yanan Chen Abstract: The structural engineering of metastable nanomaterials with abundant defects has attracted much attention in energy-related fields. The high-temperature shock (HTS) technique, as a rapidly developing and advanced synthesis strategy, offers significant potential for the rational design and fabrication of high-quality nanocatalysts in an ultrafast, scalable, controllable and eco-friendly way. This review provides an overview of various metastable micro- and nanomaterials synthesized via HTS, including single metallic and bimetallic nanostructures, high entropy alloys, metal compounds (e.g. metal oxides) and carbon nanomaterials. HTS provides a new research dimension for nanostructures, i.e. kinetic modulation. We summarize the application of HTS—as supporting films for transmission electron microscopy grids—in the structural engineering of 2D materials, which is vital for the direct imaging of metastable materials. Finally, we discuss the potential future applications of high-throughput and liquid-phase HTS strategies for non-equilibrium micro/nano-manufacturing beyond energy-related fields. It is believed that this emerging research field will bring new opportunities to the development of nanoscience and nanotechnology in both fundamental and practical aspects. Keywords: high-temperature shock technique, defect engineering, metastable phase, kinetic modulation, non-equilibrium micro/nano-manufacturing Introduction: Increasing concerns regarding global warming, environmental pollution and the energy crisis have prompted extensive exploration of sustainable energy strategies. However, economic growth decouples both energy consumption and CO₂ emissions. Full decarbonization and a carbon-neutral society with an effective and environmentally friendly energy system remains a great challenge. For instance, fuel cells, as a promising energy-storage system, have unique properties such as safety, eco-friendliness and superior activity. However, the stability of fuel cells still needs to be improved, especially at high currents. This improvement would be of great significance for industrial applications. The manufacturing process for micro- and nanocatalysts has encountered great obstacles, such as high surface tension, particle agglomeration, poor activity and stability, complicated fabrication, low producing efficiency, high cost and limited intrinsic structures. Therefore, great effort should be devoted to developing effective, cost-efficient and compelling strategies to synthesize stable and high-performing novel functional materials with unique structures and properties, such as metastable materials and amorphous or heterophase nanostructures, for advancing renewable energy storage and alleviating global warming. Metastable nanomaterials with abundant defects, including high entropy alloys (HEAs), show great potential in catalytic procedures with high performance and stability, since the electronic structure is strongly associated with the crystal configuration. Taking HEAs as an example, the main physical parameters contributing to the metastability include: (i) Complex composition. HEAs have