Effect of Al substitution on the microstructure and lithium storage performance of nickel hydroxide
Effect of Al substitution on the microstructure and lithium storage performance of nickel hydroxide
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DOI：
10.1016/j.jpowsour.2015.12.129
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发表时间：
2016-03
影响因子：
9.2
通讯作者：
L. Yanwei;Guanlin Pan;Wenqiang Xu;Jinhuan Yao;Lingzhi Zhang
中科院分区：
文献类型：
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作者：
L. Yanwei;Guanlin Pan;Wenqiang Xu;Jinhuan Yao;Lingzhi Zhang
用化学共沉淀法制备了Al ~（3+）/Ni ~（2+）摩尔比分别为0%，10%，20%的Al取代Ni（OH）_2样品。采用X射线衍射（XRD）、傅里叶变换红外光谱（FT-IR）、热重分析（TGA）和场发射扫描电子显微镜（FESEM）对样品的微观结构进行了分析。结果表明：纯Ni（OH）2样品为纳米片分级结构的β-Ni（OH）2; Al含量为10%的样品为纳米片/纳米颗粒混合分级结构的α/β-Ni（OH）2混合相; Al含量为20%的样品为纳米颗粒不规则分级结构的α-Ni（OH）2。通过循环伏安法、电化学阻抗谱和充放电测试对样品的储锂性能进行了表征。结果表明，Al的替代可以提高氢氧化镍的储锂性能。其中，Al含量为10%的α/β-Ni（OH）2混合相的电化学活性最高，倍率性能最好，循环稳定性上级。例如，在200 mA g−1的电流密度下进行30次充电/放电循环后，具有10% Al的混合相α/β-Ni（OH）2仍然可以提供964 mAh g−1的放电比容量，远高于具有20% Al的α-Ni（OH）2（681 mAh g−1）和纯Ni（OH）2（419 mAh g−1）。
Al-substituted Ni(OH)2samples with Al3+/Ni2+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)2sample isβ-Ni(OH)2with nanosheets hierarchical structure; the sample with 10% Al is mixed phaseα/β-Ni(OH)2with hybrid nanosheets/nanoparticles hierarchical structure; the sample with 20% Al isα-Ni(OH)2with irregular nanoparticles hierarchical structure. The lithium storage performances of the prepared samples are characterized by cyclic voltammograms (CV), electrochemical impedance spectroscopy (EIS), and charge–discharge tests. The results demonstrate that Al substitution could improve the lithium storage performances of nickel hydroxide. In particular, the mixed phaseα/β-Ni(OH)2with 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 g−1, the mixed phaseα/β-Ni(OH)2with 10% Al can still deliver a specific discharge capacity of 964 mAh g−1, much higher than of for theα-Ni(OH)2with 20% Al (681 mAh g−1) and the pure Ni(OH)2(419 mAh g−1).