Efficient Production of Graphene through a Partially Frozen Suspension Exfoliation Process: An Insight into the Enhanced Interaction Based on Solid–Solid Interfaces

Liquid phase exfoliation (LPE) offers a promising path for scalable graphene production, but struggles with high energy consumption and low yield, with over 99.99% of the input energy wasted. Here, we present an energy-efficient approach for producing graphene via partially frozen-suspension exfoliation (PFE). As opposed to traditional liquid-solid interfaces, the solid-solid interface enhances shear strength between the frozen solvent and graphite from about 40 N m^-2 to 10⁵ N m^-2. Additionally, the suspension flow transitions from turbulent to laminar, aligning graphite parallel to the flow direction and conducive to the effective utilization of shear force. Compared to conventional liquid-phase exfoliation (LPE), PFE improves energy efficiency by 10²∼10³ times. Furthermore, a production rate of 5 g h^-1 has been achieved in a 10 L tank at an ultralow shear rate of 3 × 10² s^-1.