Synthesis of Single Crystalline Spinel LiMn2O4 Nanowires for a Lithium Ion Battery with High Power Density
Synthesis of Single Crystalline Spinel LiMn2O4 Nanowires for a Lithium Ion Battery with High Power Density
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DOI：
10.1021/nl803394v
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发表时间：
2009-03-01
期刊：
影响因子：
10.8
通讯作者：
Zhou, Haoshen
中科院分区：
文献类型：
--
作者：
Hosono, Eiji;Kudo, Totsuichi;Zhou, Haoshen
如何提高锂离子二次电池的比功率密度已成为近年来科学界和工业界最感兴趣的课题之一。与商品化的LiCoO2相比，尖晶石LiMn2O4具有成本低、无毒等优点，是最有前途的正极材料。此外，为了满足这种工业需求，纳米结构电极已经被广泛研究。然而，基于高质量晶体的高性能正极材料所必需的高温烧结过程导致纳米粒子的尺寸较大和团聚，从而导致锂离子电池性能较差。因此，合成高质量的单晶纳米结构电极仍然是一个挑战。在所有的纳米结构中，单晶纳米线是最具吸引力的形态，因为由单晶纳米线构成的非织造布形态抑制了高温下的聚集和颗粒生长，并且纳米颗粒之间的势垒可以忽略不计。然而，已报道的单晶纳米线几乎是具有各向异性晶体结构的金属氧化物，因为立方晶体结构如LiMn2O4不易沿一维方向生长。在这里，我们以Na0.44MnO2纳米线为模板，采用一种新的反应方法合成了高质量的单晶立方尖晶石LiMn2O4纳米线。这些单晶尖晶石LiMn2O4纳米线具有较高的热稳定性，因为在800℃加热12h后，纳米线结构保持不变，在高速充放电(如20A/g)下表现出优异的性能，具有相对平坦的充放电平台和良好的循环稳定性。
How to Improve the specific power density of the rechargeable lithium ion battery has recently become one of the most attractive topics of both scientific and Industrial interests. The spinal LiMn2O4 Is the most promising candidate as a cathode material because of its low cost and nontoxicity compared with commercial LiCoO2. Moreover, nanostructured electrodes have been widely Investigated to satisfy such Industrial needs. However, the high-temperature sintering process, which is necessary for high-performance cathode materials based on high-quality crystals, leads the largo grain size and aggregation of the nanoparticles which gives poor lithium Ion battery performance. So there is still a challenge to synthesize a high-quality single-crystal nanostructured electrode. Among all of the nanostructures, a single crystalline nanowire Is the most attractive morphology because the nonwoven fabric morphology constructed by the single crystalline nanowire suppresses the aggregation and grain growth at high temperature, and the potential barrier among the nanosize grains can be Ignored. However, the reported single crystalline nanowire is almost the metal oxide with an anisotropic crystal structure because the cubic crystal structure such as LiMn2O4 cannot easily grow In the one-dimensional direction. Here we synthesized high-quality single crystalline cubic spinel LiMn2O4 nanowires based on a novel reaction method using Na0.44MnO2 nanowires as a self-template. These single crystalline spinel LiMn2O4 nanowires show high thermal stability because the nanowire structure Is maintained after heating to 800 degrees C for 12 h and excellent performance at high rate charge-discharge, such as 20 A/g, with both a relative flat charge-discharge plateau and excellent cycle stability.