期刊
SCIENTIFIC REPORTS
卷 5, 期 -, 页码 -出版社
NATURE PUBLISHING GROUP
DOI: 10.1038/srep17836
关键词
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资金
- National Natural Science Foundation of China [51502064, 51202050, 51162007]
- Fundamental Research Funds for the Central Universities [20720150034]
- Scientific Research Setup Fund of Hainan University [kyqd1532]
To explore anode materials with large capacities and high rate performances for the lithium-ion batteries of electric vehicles, defective Ti2Nb10O27.1 has been prepared through a facile solid-state reaction in argon. X-ray diffractions combined with Rietveld refinements indicate that Ti2Nb10O27.1 has the same crystal structure with stoichiometric Ti2Nb10O29 (Wadsley-Roth shear structure with A2/m space group) but larger lattice parameters and 6.6% O2- vacancies (vs. all O2- ions). The electronic conductivity and Li+ ion diffusion coefficient of Ti2Nb10O27.1 are at least six orders of magnitude and similar to 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 Ti2Nb10O29-x and its conductor characteristic. As a result of the improvements in the electronic and ionic conductivities, Ti2Nb10O27.1 exhibits not only a large initial discharge capacity of 329 mAh g(-1) and charge capacity of 286 mAh g(-1) at 0.1C but also an outstanding rate performance and cyclability. At 5C, 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%.
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