Effect of cobalt alloying on the electrochemical performance of manganese oxide nanoparticles nucleated on multiwalled carbon nanotubes
Effect of cobalt alloying on the electrochemical performance of manganese oxide nanoparticles nucleated on multiwalled carbon nanotubes
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DOI：
10.1088/1361-6528/aa6329
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发表时间：
2017-03
期刊：
影响因子：
3.5
通讯作者：
Sajad Yazdani;Raana Kashfi-Sadabad;A. Palmieri;W. Mustain;Michael Thompson Pettes
中科院分区：
文献类型：
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作者：
Sajad Yazdani;Raana Kashfi-Sadabad;A. Palmieri;W. Mustain;Michael Thompson Pettes
MnO是一种电绝缘材料，限制了它在锂离子电池中的应用。我们证明了在多壁碳纳米管（MWCNTs）外壁上形成的氧官能团作为金属氧化物纳米粒子的成核位点，可以大大提高MnO的电化学性能。根据制备电极所用活性材料的质量，x = 0.2的复合转化反应阳极材料Mn1 - xCoxO/MWCNT在电流密度为40和1600 mAg−1时的可逆比容量分别为790和553 mAhg−1。这是MnO/MWCNT在1600 mAg−1充电速率下的3.1倍。当x≤0.15时，Mn1 - xCoxO纳米颗粒中未观察到相偏析。x = 0、0.2和1电极的容量保持表明，在400 mAg−1电流密度下，经过55次循环，相应的比容量分别稳定在478、709和602 mAhg−1。由于MnO和CoO具有相似的理论容量，而MnO/MWCNT和CoO/MWCNT阳极的性能均低于mn0.8 co0.2 /MWCNT，因此Mn1 - xCoxO/MWCNT合金性能的提高可能源于双金属体系中有益的协同作用。
MnO is an electrically insulating material which limits its usefulness in lithium ion batteries. We demonstrate that the electrochemical performance of MnO can be greatly improved by using oxygen-functional groups created on the outer walls of multiwalled carbon nanotubes (MWCNTs) as nucleation sites for metal oxide nanoparticles. Based on the mass of the active material used in the preparation of electrodes, the composite conversion-reaction anode material Mn1−xCoxO/MWCNT with x = 0.2 exhibited the highest reversible specific capacity, 790 and 553 mAhg−1 at current densities of 40 and 1600 mAg−1, respectively. This is 3.1 times higher than that of MnO/MWCNT at a charge rate of 1600 mAg−1. Phase segregation in the Mn1−xCoxO nanoparticles was not observed for x ≤ 0.15. Capacity retention in x = 0, 0.2, and 1 electrodes showed that the corresponding specific capacities were stabilized at 478, 709 and 602 mAhg−1 respectively, after 55 cycles at a current density of 400 mAg−1. As both MnO and CoO exhibit similar theoretical capacities and MnO/MWCNT and CoO/MWCNT anodes both exhibit lower performance than Mn0.8Co0.2O/MWCNT, the improved performance of the Mn1−xCoxO/MWCNT alloy likely arises from beneficial synergistic interactions in the bimetallic system.