Scalable production of graphene with tunable edge functionalities via shear-driven ball milling for energy storage...

The scalable production of graphene with controlled chemical functionalities remains a central challenge in translating laboratory advances into practical technologies. Beyond conventional approaches that prioritize the surface area, functionalization or conductivity, increasing attention is being directed toward spatially selective defect engineering that preserves the aromatic π-conjugated carbon framework while enabling targeted interfacial reactivity, thereby providing high-quality graphene. In this context, shear-driven ball milling has emerged as a promising mechanochemical route for the synthesis of edge-functionalized graphene through preferential edge activation and controlled exfoliation. Unlike oxidation-intensive methods that often introduce extensive basal-plane damage, shear-assisted milling promotes layer delamination while largely preserving the intrinsic sp² carbon network. Simultaneously, the mechanochemical environment activates newly generated edge sites, enabling direct reactions with selected milling agents and facilitating controlled incorporation of heteroatoms and functional groups. Such edge-focused functionalization provides an effective means of balancing electrical conductivity, wettability, ion accessibility, and electrochemical activity. This review critically examines the mechanistic principles governing graphite exfoliation during ball milling, the roles of milling agents and processing parameters in regulating structural evolution and surface chemistry, and the characterization strategies used to distinguish edge functionalization from basal-plane modification. Particular emphasis is placed on understanding the relationships between processing conditions, defect generation, functionalization pathways, and electrochemical performance. The influence of edge-engineered graphene on charge storage mechanisms in supercapacitors, lithium-ion batteries, sodium-ion batteries, zinc-ion systems, and hybrid energy-storage devices is comprehensively discussed. In addition, key considerations related to scalability, process economics, sustainability, contamination control, energy consumption, reproducibility, and industrial implementation are evaluated. Overall, this review establishes a process-structure-electrochemistry framework for shear-driven ball-milled graphene and highlights its potential as a scalable platform for the development of advanced graphene materials tailored for next-generation energy-storage technologies.