Advanced Etching Strategies for Microstructural Control and Performance Enhancement in Metal–Ion Batteries

ABSTRACT Etching technology, an advanced method for precise micro‐/nanostructuring, demonstrates significant potential in addressing critical challenges in high‐energy‐density batteries, such as electrode structural degradation and increasing interfacial impedance. Categorized into dry and wet etching based on their underlying mechanisms, these techniques facilitate selective material removal, enabling precise control over the morphology, crystal structure, and chemical state of electrodes, electrolytes, and interfaces. Owing to its high precision, 3D processing capability, and minimal damage to intrinsic material properties, etching serves as a powerful tool for realizing sophisticated structural designs. Despite its maturity in microelectronics, a systematic review of etching techniques for battery components is still lacking. To bridge this gap, we provide the first systematic examination of etching techniques for tailoring the microstructures of all four core battery components: cathodes, anodes, separators/solid‐state electrolytes, and current collectors. Specifically, we discuss their application strategies, underlying mechanisms, and design principles. Through case studies, it highlights the unique advantages of etching in mitigating issues like volume variation, dendrite growth, sluggish ion transport, and interfacial instability. Ultimately, this review aims to deepen the understanding of etching's role in battery microstructure control and to provide novel technical pathways and foundations for designing next‐generation batteries with enhanced performance and stability.