Li4Ti5O12 Heattreated under Nitrogen Ambient with Outstanding Rate Capabilities

The powders of spinel Li4Ti5O12 were prepared by heat treating the mixture of rutile TiO2 and Li acetate at 800∘C for 3 h under a nitrogen atmosphere and, for comparison, under air as well. The powders heated under N2 show a remarkably higher-rate capability and better cycle stability. The discharge capacity of Li4Ti5O12 heated under N2 at 19°C (corresponding to a 3.2-minute total discharge) reached 107 mA h g−1, 22 mA h g−1 higher than that of Li4Ti5O12 heated under air, which was 85 mA h g−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 as N2 could significantly improve the high-rate performance of spinel Li4Ti5O12