Al-substituted Ni(OH)2 samples with Al3t/Ni2t mole ratio of 0%, 10% and 20% have been prepared by a

very facile chemical co-precipitation method. The microstructure of the prepared samples are analyzed

by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis

(TGA), and Field emission scanning electron microscopy (FESEM). The results reveal that the pure

Ni(OH)2 sample is b-Ni(OH)2 with nanosheets hierarchical structure; the sample with 10% Al is mixed

phase a/b-Ni(OH)2 with hybrid nanosheets/nanoparticles hierarchical structure; the sample with 20% Al

is a-Ni(OH)2 with irregular nanoparticles hierarchical structure. The lithium storage performances of the

prepared samples are characterized by cyclic voltammograms (CV), electrochemical impedance spectroscopy

(EIS), and chargeedischarge tests. The results demonstrate that Al substitution could improve

the lithium storage performances of nickel hydroxide. In particular, the mixed phase a/b-Ni(OH)2 with

10% Al exhibited the highest electrochemical activity, the best rate performance, and superior cycling

stability. For example, after 30 charge/discharge cycles under a current density of 200 mA g1, the mixed

phase a/b-Ni(OH)2 with 10% Al can still deliver a specific discharge capacity of 964 mAh g1, much higher

than of for the a-Ni(OH)2 with 20% Al (681 mAh g1) and the pure Ni(OH)2 (419 mAh g1).