Taming Transport Gradients: Engineered Microstructures for Fast-Charging Thick Electrodes

Pursuing higher energy density via thick electrodes inevitably intensifies lithium transport limitations and mechanical degradation, critical barriers to fast charging. The root cause lies in intrinsic gradient fluxes-ionic, electronic, and reaction-driven-along the electrode thickness due to heterogeneous electrochemical environment. This review proposes the "Match Principle" as a unifying design framework. It creates structural gradients (e.g., porosity, conductivity, particle size) along the thickness direction that align with these inherent flux gradients. Such matching optimizes local charge-transport kinetics and mitigates damage heterogeneity. In this review, the principle's theoretical foundation is first stated. Recent advances in fabricating thick electrodes that implement such gradient designs to improve performance are then summarized. Concluding perspectives further highlight advanced electrode structure manufacturing processes, advanced characterization methods, and AI-assisted design, as essential tools for the principled design and industrialization of next-generation thick electrodes.