Break the capacity limit of Li4Ti5O12 anodes through oxygen vacancy engineering

The zero-strain spinel Li₄Ti₅O₁₂ stands out as a promising anode material for lithium-ion batteries due to its outstanding cycling stability. However, the limited theoretic specific capacity, low Li⁺ diffusion coefficient and electronic conductivity severely hinder its practical application. In this study, we demonstrate a strategy of introducing abundant oxygen vacancies not only on the surface and but also inside the bulk of Li₄Ti₅O₁₂ particles via reductive thermal sintering. The oxygen vacancies can significantly enhance the electronic conductivity and lithium-ion diffusion coefficient of Li₄Ti₅O₁₂, leading to a remarkable improvement in rate performance and a reduction in polarization. Moreover, additional lithium-ion accommodation sites can be created at the defective surface, contributing to a high specific capacity of over 200 mAh g⁻¹.