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摘要
To enhance the lithium storage performance of alpha-Ni(OH)(2), different amount of Zn2+ (with Zn2+/Ni2+ molar ratio of 0 %, 15 %, 30 %, 45 %, and 60 %, respectively) was introduced into the lattice of alpha-Ni(OH)(2) samples by a facile hydrothermal method. The influence of Zn2+ doping on the microstructure and lithium storage performance of alpha-Ni(OH)(2) was investigated in detail. The results demonstrate that with the increase of Zn2+/Ni2+ molar ratio, the microstructure of the as-prepared samples transforms from an urchin-like morphology to flower-like morphology, accompanied by the phase structure transforming from pure-phase alpha-Ni(OH)(2) to mixed-phase alpha-Ni(OH)(2)/Zn(OH)(2). Electrochemical characterizations reveal that Zn2+ doping can effectively enhance the lithium storage performance of a-Ni(OH)(2). In particular, the Zn2+ doped a-Ni(OH)(2) with Zn2+/ Ni2+ molar ratio of 45 % (45-ZN) exhibits superior cycling stability (maintaining a reversible capacity of 713 mA h g(-1) at a current density of 0.5 A/g after 50 cycles), outstanding high-rate capability (delivering a high specific capacity of 485 mA h g(-1) at 2.0 A/g), and fast electrochemical reaction kinetics. GITT analysis demonstrates that the lithium ions diffusion coefficient of the 45-ZN varies in the range of 10-10 -10-12 cm(2) s(-1), higher than that (10-10-10-13 cm(2) s(-1)) of pure alpha-Ni(OH)(2.) In addition, the 45-ZN sample presents an obvious pseudocapacitance behavior during the discharging/charging process. The synergetic effect between Ni2+ and Zn2+ can account for the improved electrochemical performance of the Zn2+ doped aNi(OH)(2). The work provides clues for the preparation and performance optimization of a-Ni(OH) 2 as an anode material for lithium-ion batteries from the aspect of metal ions doping.
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单位桂林理工大学
