Hybrid Li-air battery cathodes with sparse carbon nanotube arrays directly grown on carbon fiber papers
Hybrid Li-air battery cathodes with sparse carbon nanotube arrays directly grown on carbon fiber papers
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DOI：
10.1039/c3ee41116h
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发表时间：
2013-11-01
影响因子：
32.5
通讯作者：
Xing, Yangchuan
中科院分区：
文献类型：
--
作者：
Li, Yunfeng;Huang, Zhongping;Xing, Yangchuan
在碳纤维纸上直接生长了具有位错石墨烯堆积的稀疏排列的垂直排列的氮掺杂碳纳米管阵列(CNTA)，并将其用作含水阴极的混合锂空气电池的分层空气阴极。用电沉积镍纳米催化剂，然后等离子体增强化学气相沉积制备了碳纳米管。这样得到的碳纳米管在碳纤维上的布居数密度可以达到接近每厘米10(7)个/cm(2)，获得了极高的阴极活性层孔隙率超过99%。稀疏的CNTA不仅为反应物种提供了有效的途径，而且表现出显著的高催化活性，可与负载型铂电催化剂相媲美。碳纳米管的高活性归因于碳纳米管表面暴露的丰富的石墨烯边缘和氮的掺杂。具有这种正极的混合锂空气电池在0.5 mA cm(-2)下表现出710 mA h g(-1)的稳定放电容量和2057W h kg(-1)的比能量。在0.5 mA cm(-2)的稳定充放电循环下，平均电位差为1.35V，表明过电位相对较小，往返效率较高(71%)。此外，基于分级正极的混合锂空气电池的功率密度可高达10.4 mW cm(-2)。
Sparsely populated, vertically aligned nitrogen doped carbon nanotube arrays (CNTAs) with dislocated-graphene stacking were grown directly on carbon fiber papers and investigated as hierarchical air cathodes in hybrid Li-air batteries with aqueous catholytes. The CNTAs were made with electrodeposited Ni nanocatalysts, followed by plasma-enhanced chemical vapor deposition. The thus obtained CNTAs can reach a population number density as low as similar to 10(7) per cm(2) on the carbon fibers, achieving an extremely high porosity of over 99% for the active layer in the cathode. The sparse CNTAs not only provide effective pathways for the reacting species, but also show a significantly high catalytic activity, which is found to be comparable to that of a supported Pt electrocatalyst. The high activity of the CNTAs is attributed to the rich graphene edges exposed on the CNT surface and nitrogen doping. Hybrid Li-air batteries with such cathodes have shown a consistent discharging capacity of 710 mA h g(-1) and a specific energy of 2057 W h kg(-1) at 0.5 mA cm(-2). Stable charge-discharge cycling at 0.5 mA cm(-2) showed an average potential difference of 1.35 V, indicative of a relatively small overpotential and high round trip efficiency (71%). Furthermore, the hybrid Li-air battery based on the hierarchical cathode can reach a power density as high as 10.4 mW cm(-2).