Microwave rapid preparation of LiNi0.5Mn1.5O4 and the improved high rate performance for lithium-ion batteries
Microwave rapid preparation of LiNi0.5Mn1.5O4 and the improved high rate performance for lithium-ion batteries
复制标题
微波快速制备LiNi0.5Mn1.5O4及提高锂离子电池高倍率性能
DOI：
10.1016/j.electacta.2013.03.153
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发表时间：
2013-06-30
影响因子：
6.6
通讯作者：
Yang, Gang
中科院分区：
文献类型：
--
作者：
Gao, Po;Wang, Lu;Yang, Gang
采用微波加热法在700 ℃下加热7 min快速合成了尖晶石LiNi 0.5Mn 1.5O4（MW 700 C7 m）。采用Rietveld法对MW 700 C7 m的XRD图谱进行了精细化处理，利用扫描电镜、透射电镜和氧化还原滴定法对MW 700 C7 m的晶体结构、形貌和元素缺陷进行了研究，并与700 ℃下加热48 h合成的样品（CP 700 C48 h）进行了比较。MW 700 C7 m和CP 700 C48 h都使用Fd-3 m空间群进行了很好的精制。微波辐照不仅促进了尖晶石型LiNi 0.5Mn 1.5O4晶体的生长，而且导致了晶体的择优生长行为。MW 700 C7 m的循环伏安（CV）显示出低极化和更好的结构稳定性。MW 700 C7 m和CP 700 C48 h的恒电流充放电循环除了Ni 2 +/4+氧化还原峰外，还具有较小的Mn 3 +/4+氧化还原峰。在正常电流下，MW 700 C7 m和CP 700 C48 h均表现出良好的容量，接近理论值。在高电流率下，MW 700 C7 m提供比CP 700 C48 h更好的容量。MW 700 C7 m在10 C-率下提供108.7 mAh g（-1）的容量，150次循环后衰减小于1%。LiNi0.5Mn1.5O4阴极在高温和低温下进行循环时严重的容量损失仍然是一个问题。在不同温度下，研究了Mn ~（3+）/~（4+）和Ni ~（2+）/~（4+）氧化还原对容量的贡献和影响。(c)2013爱思唯尔有限公司保留所有权利。
Spinel LiNi0.5Mn1.5O4 is rapidly synthesized by using microwave heating at 700 degrees C for 7 min (MW700C7m). The crystal structure, morphology and elemental deficiency of MW700C7m are carefully studied by Rietveld refinement of XRD patterns, scanning and transmission electron microcopy, and redox titration, in comparison with the sample synthesized by conventional heating at 700 degrees C for 48 h (CP700C48h). Both MW700C7m and CP700C48h are well refined using the Fd-3m space group. Microwave irradiation not only accelerates the crystal growth of spinel LiNi0.5Mn1.5O4, but also results in preferential growth behavior. Cyclic voltammetry (CV) of MW700C7m presents low polarization and better structural stability. Galvanostatic charge-discharge cycling of MW700C7m and CP700C48h have minor Mn3+/4+ redox peaks beside Ni2+/4+ redox peaks. At normal current rate, both MW700C7m and CP700C48h present good capacities, close to the theoretical value. At high current rate, MW700C7m delivers much better capacity than CP700C48h. MW700C7m delivers capacity of 108.7 mAh g(-1) at 10 C-rates and fades less than 1% after 150 cycles. The severe capacity loss of LiNi0.5Mn1.5O4 cathodes is still a problem when cycling is carried out at high and low temperatures. Under various temperatures, the contribution and effect of Mn3+/4+ and Ni2+/4+ redox for the capacity are studied in detail. (c) 2013 Elsevier Ltd. All rights reserved.