Synthesis of 2D Li4Ti5O12 Nanosheets via the “Insertion–Exfoliation–Lithiation” Process

Plenty of research efforts have been devoted to developing the anisotropic 2D architectures with intriguing electrochemical and optoelectronic properties. However, the scalable production of nonlayered binary metal oxides with a 2D structure still remains a great challenge. Here, we develop an “insertion–exfoliation–lithiation” process to delaminate the spinel Li4Ti5O12 (LTO) into the thickness of ∼4 nm. After the intercalation of methylamine (MA) into the H2Ti3O7 interlayers, the MA intercalated titanic acid (MA/Ti3O7) exhibits the volume expansion along the stacking direction with the interlayer spacing increasing from an original 7.9 to 10.1 A. Driven by the acid–base equilibrium and osmotic pressure balance, this crucial step significantly enhances the exfoliation yield of MA/Ti3O7 nanosheets upon the mechanical peeling process. First-principles calculation validates that 1.1 unit of MA has been inserted per mole of H2Ti3O7 described as MA1.1H0.9Ti3O7. In addition, the transmission-mode in situ X-ray ...