Enhanced stability and the lithium storage mechanism of oxygen vacancy-induced heterogeneous Li4Ti5O12/TiO2(B) anolytes

Abstract

Currently, addressing the challenges posed by the low energy density of lithium titanate (LTO), a prevalent anode material in lithium slurry batteries (LSBs), is crucial for ensuring high stability, storage capacity, and cycle stability, thereby facilitating the commercialization of LSBs. In this study, a heterostructure (LTO-TOB) was created by integrating nano-TiO₂(B) (bronze phase) onto the surface of commercial LTO. The coated TiO₂(B) layer significantly increases the specific surface area and wettability, guaranteeing fantastic stability. The pseudo-capacitance lithium storage ability of TiO₂(B) boosts the power of the electrochemical reaction. The extra interface in the crystalline phase and the presence of oxygen vacancies serve not just as lithium storage sites, but also accelerate the Li⁺ diffusivity and enhance the electron conductivity. Furthermore, the diffusion mechanism of lithium ions within LTO-TOB anolyte was examined by using a designed in situ Raman cell. The engineered LTO-TOB anolyte assembled reactor boasts a substantial specific capacity of 209.12 mA h g⁻¹ at 0.5C, coupled with remarkable cycle steadiness (with a mere 0.095% capacity loss per 100 cycles). The reactor exhibits favorable electrochemical characteristics in both intermittent mode and static long-term cyclic mode, thereby highlighting the significance of surface heterostructure modification as a key approach in advancing the progress of LSBs.