文章基本信息

标题：Defective Ti₂Nb₁₀O_27.1: an advanced anode material for lithium-ion batteries
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作者：Chunfu Lin ; Shu Yu ; Hua Zhao 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：5
DOI：10.1038/srep17836
出版社：Springer Nature
摘要：To explore anode materials with large capacities and high rate performances for the lithium-ion batteries of electric vehicles, defective Ti₂Nb₁₀O_27.1 has been prepared through a facile solid-state reaction in argon. X-ray diffractions combined with Rietveld refinements indicate that Ti₂Nb₁₀O_27.1 has the same crystal structure with stoichiometric Ti₂Nb₁₀O₂₉ (Wadsley-Roth shear structure with A2/m space group) but larger lattice parameters and 6.6% O^2– vacancies ( vs. all O^2– ions). The electronic conductivity and Li⁺ion diffusion coefficient of Ti₂Nb₁₀O_27.1 are at least six orders of magnitude and ~2.5 times larger than those of Ti₂Nb₁₀O₂₉, respectively. First-principles calculations reveal that the significantly enhanced electronic conductivity is attributed to the formation of impurity bands in Ti₂Nb₁₀O_{29– x} and its conductor characteristic. As a result of the improvements in the electronic and ionic conductivities, Ti₂Nb₁₀O_27.1 exhibits not only a large initial discharge capacity of 329 mAh g^–1 and charge capacity of 286 mAh g^–1 at 0.1 C but also an outstanding rate performance and cyclability. At 5 C, its charge capacity remains 180 mAh g^–1 with large capacity retention of 91.0% after 100 cycles, whereas those of Ti₂Nb₁₀O₂₉ are only 90 mAh g^–1 and 74.7%.