Titanium dioxide (TiO2) is a promising electrode material for reversible lithium storage. However, the poor electronic conductivity, sluggish diffusivity, and intrinsic kinetics limit hinder its fast lithium storage capability. Here we present that the oxygen‐deficient TiO2hierarchical spheres can address the issues for high capacity, long‐term lithium‐ion battery anode. First‐principles calculations show that introducing oxygen vacancies to anatase TiO2can reduce the bandgap, thus improving the electronic conductivity and further the lithium storage properties of TiO2. By annealing TiO2/H2Ti5O11⋅3H2O hierarchical spheres precursor in nitrogen, accompanying with the phase transfer process, the growth of TiO2crystallites is restricted due to the generation of residual carbon species, resulting in a well maintained hierarchical spherical structure. Rich oxygen vacancies are generated in the oxygen‐deficient environment and evidenced by EPR, XPS, and UV‐Vis spectra, which enable the TiO2hierarchical spheres reduced bandgap. The oxygen vacancies in the as‐obtained TiO2hierarchical spheres together with the high structural integrity of the hierarchical spheres gives rise to superior lithium storage properties including a high specific capacity of 282 mAh g−1at 200 mA g−1, and long‐term cycling stability with a capacity retention of 85.2 % at 4 A g−1over 10000 cycles.
Anatase TiO2is a promising anode material for lithium‐ion batteries (LIBs) owing to its low cost and stability. However, the intrinsically kinetic limits seriously hindered its lithium‐ion storage capability. Here we present that anatase TiO2with rich oxygen vacancies can enhance its lithium‐ion storage performance. We synthesize anatase TiO2with well‐retained hierarchical structure by annealing the H2Ti5O11·3H2O yolk‐shell spheres precursor in nitrogen atmosphere. EPR and XPS data evidence that the oxygen‐deficient environment could generate abundant oxygen vacancies in the as‐derived anatase TiO2, which leads to improved electron conductivity and reduced charge‐transfer resistance. The rich oxygen vacancies and high structural integrity of the hierarchical yolk‐shell spheres enable the as‐derived anatase TiO2yolk‐shell spheres with a high specific capacity of 280 mAh g−1at 100 mA g−1and 71% of capacity retention after 5000 cycles at 2 A g−1.
more » « less- NSF-PAR ID:
- 10447353
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ENERGY & ENVIRONMENTAL MATERIALS
- Volume:
- 5
- Issue:
- 1
- ISSN:
- 2575-0356
- Page Range / eLocation ID:
- p. 238-244
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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