Rational Design of High‐Voltage Lithium‐Ion Batteries: From Multiscale Mechanisms to Scalable Manufacturing

High‐voltage lithium‐ion batteries (HVLIBs) are increasingly considered promising candidates for meeting the growing demand for high energy density and extended cycle life in electric vehicles and grid‐level energy storage. However, the performance and stability of HVLIBs are critically influenced by fabrication techniques, including dry/wet processing, in situ polymerization, and advanced electrode engineering. These methods shape the architecture of electrodes and directly affect the electrochemical behavior under high‐voltage conditions, where challenges such as electrolyte oxidation, gas evolution, and cathode degradation become more accelerated. The fabrication processes are inherently coupled with multiscale phenomena, from atomic‐level redox reactions and interfacial reconstruction to microscale mechanical failure and system‐scale safety issues. In this review, we focus on recent advances in the processing and structural design strategies for HVLIBs, emphasizing how these approaches interact with complex physicochemical mechanisms across multiple scales. We discuss state‐of‐the‐art characterization tools, multiscale modeling, and data‐driven techniques that are employed to elucidate the intricate correlations between processing, structure, and performance. Finally, we identify key challenges and propose future directions to integrate scalable fabrication techniques with mechanistic insights, aiming to enable the rational design of next‐generation high‐voltage lithium‐ion batteries.