NON-TECHNICAL SUMMARY: This research project investigates how missing oxygen atoms, known as oxygen vacancies, affect the performance of titanium niobium oxide (TiNb2O7), a promising material for fast-charging, next-generation lithium-ion batteries. The goal is to understand how these atomic-scale defects affect the way lithium and oxygen atoms move through the material, and how they impact its ability to store and release energy quickly and reliably. By combining computer simulations with cutting-edge experimental techniques, including advanced synthesis, characterization, and performance testing, the researchers aim to uncover the role of oxygen vacancies in battery behavior. This knowledge supports the development of safer, longer-lasting, and faster-charging batteries, helping to strengthen U.S. leadership in energy innovation. The project also provides hands-on training for students and engages the community through outreach programs that promote interest in science, energy, and materials discovery. TECHNICAL SUMMARY: This project aims to establish a quantitative, fundamental understanding of how oxygen vacancies influence lithium and oxygen diffusion, ionic and electronic conductivity, and interfacial behavior in TiNb2O7, a promising high-rate oxide anode material for next-generation lithium-ion batteries. The research comprises three integrated tasks: (1) atomistic modeling of lithium and oxygen diffusion and electronic structure in oxygen-deficient composit