Li4Ti5O12Heattreated under Nitrogen Ambient with Outstanding Rate Capabilities

Rui Xu,Zilong Tang,Zhongtai Zhang,Junrong Li

doi:10.1155/2011/635416

Abstract

The powders of spinel Li4Ti5O12were prepared by heat treating the mixture of rutile TiO2and Li acetate at800∘Cfor 3 h under a nitrogen atmosphere and, for comparison, under air as well. The powders heated underN2show a remarkably higher-rate capability and better cycle stability. The discharge capacity of Li4Ti5O12heated underN2at 19°C (corresponding to a 3.2-minute total discharge) reached 107 mA hg−1, 22 mA hg−1higher than that of Li4Ti5O12heated under air, which was 85 mA hg−1. The former material also shows a much better cycle stability, with no discharge capacity loss after 300 cycles at 6°C or 16.3°C. The results indicate that heat treatment under low-oxygen partial pressure atmosphere such asN2could significantly improve the high-rate performance of spinel Li4Ti5O12.

Highlights

There has been increasing interest in developing spinel lithium titanate (Li4Ti5O12) as a potential anode for application in lithium ion rechargeable batteries [1,2,3,4,5,6,7,8,9,10,11,12,13,14] due to its long cycle life, excellent lithium ion intercalation and deintercalation reversibility, and “zero-strain” intercalation characteristics
The only difference between the two X-ray diffraction (XRD) patterns is that the diffraction peaks for the sample heated under N2 are slightly shifted to the lower 2θ values compared to the one heated under air
The spinel Li4Ti5O12 powders were prepared by heat treating the mixture of rutile TiO2 and Li acetate under nitrogen atmosphere, and, for comparison, under air

Summary

Introduction

There has been increasing interest in developing spinel lithium titanate (Li4Ti5O12) as a potential anode for application in lithium ion rechargeable batteries [1,2,3,4,5,6,7,8,9,10,11,12,13,14] due to its long cycle life, excellent lithium ion intercalation and deintercalation reversibility, and “zero-strain” intercalation characteristics. In order to increase Li4Ti5O12 conductivity, several strategies have been taken, including incorporating a conducting second phase such as Ag [16], Cu [17], CuOx [18], or Li2CuTi3O8 [19], doping with alien-valent metal ions such as Ta5+ [20] or Al3+ [21], and synthesizing nanosized [22, 23] Li4Ti5O12. Another effective method is heat treating Li4Ti5O12 under a reduced or low-oxygen partial pressure atmosphere [24]. X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) observations, and galvanostatic discharge/charge tests were used to characterize the material

Experimental

Results and Discussion

Conclusions