Crucial role of water content on the electrochemical performance ofα-Ni(OH)2as an anode material for lithium-ion batteries

In this work, we investigate the influence of water content on the lithium storage performance of alpha-Ni(OH)(2)samples prepared by homogeneous precipitation method and subsequent heat treatment at different temperatures. It is found that the adsorbed water in alpha-Ni(OH)(2)has a decisive impact on the cycling stability and rate capability of the electrode; in contrast, the effect of interlayer water contents is not significant. For example, the alpha-Ni(OH)(2)sample with adsorbed water molecules (heat-treated at 100 degrees C) delivers a reversible specific capacity of 1115 mAh g(-1)at 500 mA g(-1)after 30 cycles, while the alpha-Ni(OH)(2)sample after removing the adsorbed molecules (heat-treated at 150 degrees C) gives a capacity of only 516 mAh g(-1)under the same measurement condition. EIS and CV analyses reveal that the adsorbed water molecules in alpha-Ni(OH)(2)decrease the electrochemical reaction resistance, increase lithium ion diffusivity, and greatly enhance the pseudocapacitive charge storage behavior, which lead to superior performance in cycle life and rate capability.