Novel spinel Li5Cr9Ti4O24 anode: Its electrochemical property and lithium storage process

Abstract

In this work, a novel lithium storage material Li5Cr9Ti4O24 is reported as anode material for rechargeable lithium-ion batteries. We prepare Li5Cr9Ti4O24 by two different routes, sol-gel method and solid state reaction. Li5Cr9Ti4O24 nanocrystalline can be achieved by sol-gel method, while solid state reaction delivers micro-sized product. Electrochemical results show that Li5Cr9Ti4O24 nanocrystalline exhibits reduced charge transfer resistance, decreased redox polarization and improved lithium-ion diffusion coefficient compared with micro-sized product. As a result, Li5Cr9Ti4O24 nanocrystalline shows excellent lithium storage capability with 100% capacity retention after 200 cycles. Cycled at 600mAg−1, it still can deliver a charge specific capacity of 110.3mAhg−1. In contrast, micro-sized Li5Cr9Ti4O24 only reveals the reversible capacity of 66.8mAhg−1 at the same current density. In addition, Li5Cr9Ti4O24 nanocrystalline also shows outstanding structural stability for repeated lithium storage. In-situ structural observation reveals that the entire volume expansion of Li5Cr9Ti4O24 is only 0.62% during the charge/discharge process, which is similar with the zero-strain Li4Ti5O12. Therefore, Li5Cr9Ti4O24 nanocrystalline can be used as high performance anode material for lithium-ion batteries.