Electrochemical property of hierarchical flower-like α-Ni(OH)2 as an anode material for lithium-ion batteries

Transition metal hydroxides (TMHs) are recently receiving increasing attention as anode materials for lithium-ion batteries (LIBs) because of their merits of high theoretical capacity, low cost, and easy preparation. Herein, hierarchical flower-like alpha-Ni(OH)(2) is synthesized by a facile homogeneous precipitation method with Ni (NO3)(2)center dot 6H(2)O and urea as raw materials. When evaluated as an anode material for lithium-ion batteries, the alpha-Ni (OH)(2) delivers a high reversible capacity of 1346 mA h g(-1) at a current density of 0.05 A g(-1), and gives a reversible capacity of 475 mA h g(-1) at a high current density of 5.0 A g(-1). It maintains a reversible capacity of 1227 mA h g(-1) after 30 cycles at 0.1 A g(-1), with a capacity retention of 97.0% compared to the second cycle. The charge storage mechanism and kinetics of the alpha-Ni(OH)(2) are analyzed by sweep voltammetry method and electrochemical impedance spectroscopy. The results demonstrate that the lithium ion storage process in the alpha-Ni (OH)(2) is mainly dominated by pseudocapacitive behavior, which is responsible for the superior rate capability; the charge-transfer resistance of the alpha-Ni(OH)(2) is sensitive to the state of charge; the apparent lithium ion diffusion coefficient of the alpha-Ni(OH)(2) varies in the range of 10(-14)-10(-15) cm(2) s(-1).

Automated summary

Transition metal hydroxides (TMHs), especially hierarchical flower-like alpha-Ni(OH)(2), are attracting attention as anode materials for lithium-ion batteries due to their high reversible capacity and superior rate capability. The charge-storage mechanism and kinetics of alpha-Ni(OH)(2) are mainly controlled by pseudocapacitive behavior, demonstrating its potential for high-performance LIBs.