Facile synthesis of Li4Ti5O12/C composite with super rate performanceElectronic supplementary information (ESI) available: TG curves of the prepared Li4Ti5O12/C; charge and discharge curves of Li4Ti5O12/C with CTAB concentration of 6.5 g L−1. See DOI: 10.1039/c2ee22591c

• Main Authors: Li, Baohua, Han, Cuiping, He, Yan-Bing, Yang, Cheng, Du, Hongda, Yang, Quan-Hong, Kang, Feiyu
• Format: Article
• Language: English
• ISSN: 1754-5692; 1754-5706
• DOI: 10.1039/c2ee22591c

The Li 4 Ti 5 O 12 /C composite with lump morphology and excellent rate performance are synthesized using a facile hydrothermal method followed by a low temperature heat treatment. In the hydrothermal process, the introduction of cetyltrimethylammonium bromide (CTAB) as a surfactant significantly improves the rate performance of Li 4 Ti 5 O 12 /C composite as anode material for lithium ion battery (LIB). The specific capacities of the obtained composite at charge and discharge rates of 0.1, 1, 5, 10 and 20 C are 176, 163, 156, 151 and 136 mA h g −1 , respectively, which is apparently larger than those of the Li 4 Ti 5 O 12 /C free from CTAB in the preparation. The Li 4 Ti 5 O 12 /C prepared in presence of CTAB also shows excellent cycling performance at high rate, which is attributed to its larger diffusion coefficient of lithium ion (6.82 × 10 −12 cm 2 s −1 ) and smaller charge-transfer resistance ( R ct ) (19.2 Ω) than those of the composite (1.22 × 10 −13 cm 2 s −1 and 50.2 Ω) free from CTAB in the preparation. The Li 4 Ti 5 O 12 particles obtained in presence of CTAB are coated uniformly by a thin carbon layer with a thickness of ∼1 nm, whereas the Li 4 Ti 5 O 12 particles obtained in absence of CTAB are covered by relatively thick surface layers with a thickness of ∼2.5 nm, which is too thick, blocks the lithium ion diffusion and leads to low ionic conductivity. Introduction of CTAB in the hydrothermal process results in a lump-like Li 4 Ti 5 O 12 /C with super rate performance.