A New Spinel-Layered Li-Rich Microsphere as a High-Rate Cathode Material for Li-Ion Batteries
A New Spinel-Layered Li-Rich Microsphere as a High-Rate Cathode Material for Li-Ion Batteries
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DOI：
10.1002/aenm.201400062
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发表时间：
2014-08-05
影响因子：
27.8
通讯作者：
Li, Liping
中科院分区：
文献类型：
--
作者：
Luo, Dong;Li, Guangshe;Li, Liping
富锂层状材料被认为是锂离子电池的有前途的低成本阴极，但尽管在表面涂层或外来掺杂方面做出了努力，但它们的倍率性能较差。本文报道了尖晶石层状富锂Li-Mn-Co-O微球作为一种新型高倍率锂离子电池正极材料。合成过程相对简单，包括在溶剂热条件下形成均匀的碳酸盐前体，并随后将其转化为组装的微球，该微球通过热处理将尖晶石状组分与层状组分整合在一起。当在700 ℃下煅烧时，Li-Mn-Co-O微球中的过渡金属Mn和Co的量保持与在800 ℃下相似，而组成颗粒的结构部分地从2D转变为3D通道。因此，当作为锂离子电池正极进行测试时，在700摄氏度下获得的尖晶石层富锂Li-Mn-Co-O微球在2.0和4.6 V之间的1200 mA g（-1）的极高电流密度下显示出185.1 mA h g（-1）的最大放电容量。这样的容量是迄今为止报道的高充放电速率下的最高容量之一。因此，本发明的尖晶石层状富Li Li-Mn-Co-O微球代表了用于锂离子电池的高倍率电极材料的有吸引力的替代物。
Li-rich layered materials are considered to be the promising low-cost cathodes for lithium-ion batteries but they suffer from poor rate capability despite of efforts toward surface coating or foreign dopings. Here, spinel-layered Li-rich Li-Mn-Co-O microspheres are reported as a new high-rate cathode material for Li-ion batteries. The synthetic procedure is relatively simple, involving the formation of uniform carbonate precursor under solvothermal conditions and its subsequent transformation to an assembled microsphere that integrates a spinel-like component with a layered component by a heat treatment. When calcined at 700 degrees C, the amount of transition metal Mn and Co in the Li-Mn-Co-O microspheres maintained is similar to at 800 degrees C, while the structures of constituent particles partially transform from 2D to 3D channels. As a consequence, when tested as a cathode for lithium-ion batteries, the spinel-layered Li-rich Li-Mn-Co-O microspheres obtained at 700 degrees C show a maximum discharge capacity of 185.1 mA h g(-1) at a very high current density of 1200 mA g(-1) between 2.0 and 4.6 V. Such a capacity is among the highest reported to date at high charge-discharge rates. Therefore, the present spinel-layered Li-rich Li-Mn-Co-O microspheres represent an attractive alternative to high-rate electrode materials for lithium-ion batteries.