Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. Bldg. 11, 1113, Sofia, Bulgaria.
Dalton Trans. 2011 Jul 28;40(28):7385-94. doi: 10.1039/c1dt10515a. Epub 2011 Jun 17.
Dittmarite-type compound KMnPO(4)·H(2)O was used as a new precursor for the synthesis of nanostructured LiMnPO(4) phospho-olivines with a plate-like morphology at low temperature (about 200 °C) and a short reaction time (90-180 min). The dehydration of KMnPO(4)·H(2)O was studied by DTA and TG analysis. Structural and morphological characterization of both KMnPO(4)·H(2)O and LiMnPO(4) was performed by powder XRD, SEM and TEM analyses. The formation of nanostructured LiMnPO(4) was examined by electron paramagnetic resonance spectroscopy and TEM. It was found that the reaction between KMnPO(4)·H(2)O with the LiCl-LiNO(3) mixture includes a fast ionic exchange of K(+) with Li(+) in the framework of the dittmarite structure, followed by H(2)O release and the formation of the olivine-type structure. The morphology and texture of the dittmarite-type precursor results in a plate-like morphology of LiMnPO(4) with a preferred orientation along the [100] direction. The plate-like morphology of LiMnPO(4) is stable after annealing at 500 °C. The plates are composed of nanocrystallites, with various sizes in the range 10-20 nm. The EPR signal of LiMnPO(4) is due to the exchange-coupled Mn(2+) ions. It was demonstrated that the EPR line-width correlates with the Scherrer crystallite size.
采用 Dittmarite 型化合物 KMnPO(4)·H(2)O 作为前驱体，在低温（约 200°C）和短反应时间（90-180 分钟）下合成具有层状形貌的纳米结构 LiMnPO(4)磷橄榄石。通过 DTA 和 TG 分析研究了 KMnPO(4)·H(2)O 的脱水过程。通过粉末 XRD、SEM 和 TEM 分析对 KMnPO(4)·H(2)O 和 LiMnPO(4)的结构和形貌进行了表征。通过电子顺磁共振光谱和 TEM 研究了纳米结构 LiMnPO(4)的形成。结果表明，KMnPO(4)·H(2)O 与 LiCl-LiNO(3)混合物之间的反应包括 dittmarite 结构骨架中 K(+)与 Li(+)的快速离子交换，随后释放 H(2)O 并形成橄榄石结构。Dittmarite 型前驱体的形貌和结构导致 LiMnPO(4)具有沿[100]方向择优取向的层状形貌。在 500°C 退火后，LiMnPO(4)的层状形貌仍然稳定。这些层状由纳米晶组成，尺寸在 10-20nm 之间。LiMnPO(4)的 EPR 信号归因于交换耦合的 Mn(2+)离子。证明 EPR 线宽与谢乐晶粒尺寸相关。
