Porous- and hollow-structured LiNb 3 O 8 anode material was prepared by a hydrothermal-assisted sintering strategy for the first time. The phase evolution was studied, and the formation mechanism of the porous and hollow structure was proposed. The formation of the unique structure can be attributed to the local existence of liquid phase because of the volatilization of Li element. As the anode material, the initial discharge capacity is 285.1 mAhg −1 at 0.1 C, the largest discharge capacity reported so far for LiNb 3 O 8 . Even after 50 cycles, the reversible capacity can still maintain 77.6 mAhg −1 at 0.1 C, about 2.5 times of that of LiNb 3 O 8 samples prepared by traditional solid-state methods. The significant improvement of Li storage capacity can be attributed to the special porous and hollow structure, which provides a high density of active sites and short parallel channels for fast intercalation of Li + ions through the surface.
Hollow structure LiNb 3 O 8 photocatalysts were prepared by a hydrothermal method assisting sintering process. The particles’ aggregation to form hollow structures with obvious cavities can be attributed to the Li element volatilization during calcination process. All the LiNb 3 O 8 powders show high photocatalytic efficiency of degradation of methylene blue (MB), especially for the sample calcined at 700 °C (LNO700), with only 3 h to completely decompose MB. The photo-degradation of MB follows the pseudo-first-order kinetics, and the obtained first-order rate is 0.97/h. The larger degradation rate of LNO700 can be attributed to its hollow structure which provides a larger specific surface area and more active sites to degrade the MB molecules. The cycling test of photo-degradation and adsorption of MB over LNO700 powder indicates that the hollow structure of the LiNb 3 O 8 photocatalyst is stable and the LiNb 3 O 8 photocatalyst is an efficient photocatalyst with good reusability, confirmed by the XRD and X-ray photoelectron spectroscopy tests before and after photo-degradation of MB.
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