Li-ion storage in morphology tailored porous hollow Cu2O nanospheres fabricated by Ostwald ripening
Li-ion storage in morphology tailored porous hollow Cu2O nanospheres fabricated by Ostwald ripening
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DOI：
10.1039/c6ra22839a
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发表时间：
2016-11
期刊：
影响因子：
3.9
通讯作者：
Shilpa;Prabhakar Rai;Ashutosh Sharma
中科院分区：
文献类型：
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作者：
Shilpa;Prabhakar Rai;Ashutosh Sharma
采用Ostwald成熟方法成功合成了具有定制空心结构的均匀Cu2O纳米球，并将其用作锂离子电池的阳极。在室温下，硝酸铜与肼发生了简单的化学反应。联氨作为碱和还原剂，将Cu2+转化为Cu2O纳米粒子，Cu2O纳米粒子由于界面能大而自组装，形成100-400 nm的纳米球。采用SEM、TEM、XRD、UV-vis光谱和BET技术对制备的Cu2O纳米球进行了表征。这些Cu2O纳米球由介孔外壳（20-50 nm）和中空内部（50-100 nm）组成。通过不同电流密度下的恒流充放电测量、慢扫描循环伏安法（CV）和阻抗测量来分析Cu2O纳米球的电化学性能。空心Cu2O纳米球在100 mA g - 1电流密度下的容量为~ 650 mA h g - 1，循环100次后容量保持率大于80%。电极性能的增强归功于介孔中空纳米结构，它保证了电化学位点的增加，更短的Li离子扩散长度促进了快速的电化学动力学，以及足够的空隙空间来缓冲体积膨胀。
Uniform Cu2O nanospheres with tailored hollow structure are successfully synthesized by employing the Ostwald ripening approach, and used as anodes in Li-ion battery. The synthesis involved a facile room-temperature chemical reaction of cupric nitrate with hydrazine. Hydrazine served as an alkali and reducing agent, converting Cu2+ to Cu2O nanoparticles, which self-assembled due to their large interfacial energy and formed 100–400 nm nanospheres. The Cu2O nanospheres were characterized by SEM, TEM, XRD, UV-vis spectroscopy and BET techniques. These Cu2O nanospheres were comprised of a mesoporous shell (20–50 nm) and a hollow interior part (50–100 nm). Galvanostatic charge–discharge measurements at different current densities, slow scan cyclic voltammetry (CV) and impedance measurements were used to analyze the electrochemical performance of the Cu2O nanospheres. The hollow Cu2O nanospheres exhibited a capacity of ∼650 mA h g−1 at 100 mA g−1 current density, showing greater than 80% capacity retention after 100 cycles. The enhanced electrode performance is attributed to the mesoporous hollow nanostructure that ensured an increased number of electrochemical sites, shorter Li ion diffusion lengths facilitating fast electrochemical kinetics, and sufficient void spaces to buffer the volume expansion.