Shift of redox potential and kinetics in Lix(MnyFe1-y)PO4
Shift of redox potential and kinetics in Lix(MnyFe1-y)PO4
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DOI：
10.1016/j.jpowsour.2008.07.085
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发表时间：
2009-04-01
影响因子：
9.2
通讯作者：
Miyashiro, Hajime
中科院分区：
文献类型：
--
作者：
Kobayashi, Genki;Yamada, Atsuo;Miyashiro, Hajime
橄榄石型LiMPO4(M=Mn，Fe，Co，Ni)材料具有较高的氧化还原电势，这在很大程度上是由于M-O-P诱导效应增加了过渡金属原子的离子性质。这里，我们确定了略微但系统地改变氧化还原电势的附加微扰效应。在橄榄石LiMPO4骨架中，锰取代铁使Fe3+/Fe2+和Mn3+/Mn2+氧化还原电势都提高了约0.1V。在整个Li-x(MnyFe1-y)PO4体系中，锰取代后的总体积膨胀可能会增加金属-氧化物的平均键长，从而增加每种过渡金属的离子性。单个电池中的电压漂移很小，但在存在大量串联连接的较大规模的电池中应该很明显。还研究了Fe3+/Fe2+和Mn3+/Mn2+氧化还原反应的动力学位移。(C)2008爱思唯尔B.V.保留所有权利。
The relatively high redox potential in the olivine-type LiMPO4 (M = Mn, Fe, Co, Ni) materials has largely been explained by the M-O-P inductive effect which increases the ionic character of transition metal atoms. Here, we identify the additional perturbative effect that slightly but systematically shifts the redox potential. The substitution of iron by manganese in the olivine LiMPO4 framework raises both of the Fe3+/Fe2+ and Mn3+/Mn2+ redox potentials by similar to 0.1 V. The overall volume expansion upon Mn substitution in the whole Li-x(MnyFe1-y)PO4 system possibly increases the average metal-oxide bond length and hence the ionicity of each transition metal. The voltage shift in a single cell is small but should be significant in a larger-scale battery where there exist a large number of series connections. The kinetic shift for each of the Fe3+/Fe2+ and Mn3+/Mn2+ redox reactions is also investigated. (C) 2008 Elsevier B.V. All rights reserved.