Pressure-induced high performance Li4Ti5O12-Li2Ti3O7 defect electrode

Abstract

Due to the fact that the diffusion of ions in lithium titanate is mainly controlled by the diffusion kinetics of metastable intermediates along the twisted octahedral interface, it is possible to obtain high-performance titanium-based anodes via adding more alternative diffusion paths or increasing the contact probability between lithium ions and lithium polyhedral. Here, Li4Ti5O12 (LTO) is modified with a metastable phase Li2Ti3O7 containing twisted octahedron as an additive, and the composites (denoted as LTO-C) with superior diffusion kinetics are obtained via high-pressure and high-temperature (HPHT) technology. Interestingly, the effect of high pressure causes lattice oxygen escape and generates abundant structural defects in the LTO-C sample, which significantly ameliorates the insufficient conductivity of the titanium-based anodes while providing more energy storage sites for charge transfer. LTO-C demonstrates a reversible capacity of 185 mAh g−1 at a current density of 2000 mA g−1. This technology provides a new pathway for the preparation of composite materials and inspires the functional design of energy materials.