Fundamentals to Prospects: Synthetic Tuning of Covalent Organic Frameworks for Solid-State Hydrogen Storage.

Achieving optimal hydrogen storage performance in covalent organic frameworks (COFs) requires precise synthetic tuning to balance pore architecture, functionalization, and structural stability while ensuring scalability. However, significant challenges remain in translating laboratory-scale advancements into practical applications. This review critically examines the key challenges in COF synthesis, including the trade-off between porosity and functionalization, the need for precise control over hierarchical pore structures, and limitations in reproducibility and large-scale fabrication. We highlight the bottlenecks in current synthetic strategies, such as the difficulty in maintaining crystallinity while achieving high hydrogen binding affinity, and the challenges of integrating scalable synthesis techniques without compromising material performance. We explore emerging scalable synthesis approaches, including microwave-assisted, mechanochemical, and interfacial synthesis, which offer pathways toward industrial feasibility. Additionally, we discuss the future prospects of COF design, emphasizing the role of machine learning, high-throughput screening, and predictive modeling in accelerating material discovery and optimization. By integrating computational and experimental insights, we propose a data-driven roadmap for guiding the rational design of COFs, aiming to bridge the gap between fundamental research and practical hydrogen storage applications.