Pressure-induced phase transition toward high symmetry in zero-strain Li2TiO3

As a typical layered oxide material, Li2TiO3 has attracted considerable attention in the energy revolution and military industries, owing to its lithium-rich and “zero-strain” characteristics. However, its phase-transition behavior under high pressure remains unclear. Herein, we report a second-order phase transition from the monoclinic phase to a higher-symmetry phase in nano-polycrystalline Li2TiO3 at 43 GPa by in situ high-pressure Raman experiments and first-principles calculations at 300 K. As validated by the experiments and calculations, the distortion of layered oxide-TiO6 in Li2TiO3 is crucial in the phase transition. By modulating the gap between octahedral-TiO6 layers, we propose a potential Li2TiO3 structural model for improving the electrochemical performance of lithium-ion batteries. Our findings suggest that, based on its high-pressure phase, Li2TiO3 is a promising candidate for layered cathode materials and solid tritium breeding materials for lithium-ion batteries.