Incorporation of Li into MnOOH: An In Situ X-ray and Neutron Diffraction Study

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• 作者：Gareth R. Williams ; Alexander J. Norquist ; Dermot O'Hare
• 刊名：Chemistry of Materials
• 出版年：2006
• 出版时间：August 8, 2006
• 年：2006
• 卷：18
• 期：16
• 页码：3801 - 3807
• 全文大小：483K
• 年卷期：v.18,no.16(August 8, 2006)
• ISSN：1520-5002

文摘

In situ X-ray and neutron diffraction techniques were used to study the synthesis of LiMnO₂ from-MnOOH and LiOH under mild hydrothermal conditions. These complementary techniques allow forboth good time (X-rays) and good peak (neutrons) resolution. After a significant induction period, theformation of LiMnO₂ occurs rapidly and without transient intermediates. The Avrami-Erofe'ev modelhas been used to deduce the reaction mechanism, which is believed to involve shearing of vertex linksin the MnOOH starting material and the condensation of chains into layers. The mechanism involvesdeceleratory nucleation and 1D propagation of the layers perpendicular to the layer planes. The activationenergy is 81.2 kJ mol^-1 for the reaction between LiOH and MnOOH and 150.2 kJ mol^-1 for the LiOD/MnOOD reaction. These values are consistent with nucleation control: the difference between the twovalues is ascribed to the kinetic isotope effect.