Kg-Scale Synthesis of Ultrathin Single-Crystalline MOF/GO/MOF Sandwich Nanosheets with Elevated Electrochemical Performance

The scalable preparation of 2D ultrathin metal–organic framework (MOF) nanosheets remains a significant challenge due to low stripping efficiency and susceptibility to agglomeration. Herein, a facile strategy is developed for the synthesis of 2D ultrathin single-crystal MOF/graphene oxide (GO)/MOF (MGM) sandwich-like nanosheets based on the Ni/Co-BDC MOF (BDC = 1,4-terephthalic acid), with GO serving as a structure-directing agent. Impressively, 1 kg of MGM nanosheets can be obtained in a single batch with a metal-based yield of 98.73%. Furthermore, the universality of this strategy is implemented by the successful synthesis of three additional 2D ultrathin nanosheets: MGM₇-ABDC, MGM₇-FBDC, and MGM₇-BPDC (metal = Ni, Co; ligands = 2-aminoterephthalic acid (2-ABDC), 2-fluoroterephthalic acid (2-FBDC), and 4,4′- biphenyl dicarboxylic acid (BPDC)). The as-prepared MGM₇ nanosheets (Ni: Co ratio = 7:3) exhibit excellent electrochemical performance as the cathode for aqueous basic zinc battery (159.2 mA h g⁻¹ at 1 A g⁻¹), anode for sodium-ion battery (SIB, 593.0 mA h g⁻¹ at 0.2 A g⁻¹), and electrocatalyst for the oxygen evolution reaction (OER, 224 mV overpotential at 10 mA cm⁻²), significantly outperforming both bulk MOFs and conventional MOF nanosheets. This work enables the scalable synthesis of 2D MOF nanosheets with enhanced properties for multiple applications.