空气条件下高温固相合成层状LiMnO_2及其离子交换的影响规律

Synthesis of LiMnO_2 by Solid State Reaction in Air and the Influence of Ion Exchange Conditions on Its Structure

在空气中高温固相反应合成了层状单斜结构前驱体 Na Mn O2 ,在不同条件下进行离子交换反应 ,得到Li Mn O2 .用 X射线衍射法表征了前驱体及交换产物的晶体结构 ,用电感耦合等离子体光谱进行元素含量分析 ,用扫描电镜测定晶体的形貌 .结果表明 ,离子交换反应条件对反应速率和产物的晶体结构与组成有重要影响 .

Layered sodium manganese bronze NaMnO 2 with a monoclinic structure has been synthesized in air. Its structure is similar to the bronze synthesized in argon. The precursor was used to prepare layered LiMnO 2 by ion exchange of Na + by Li + under different ion exchange conditions: in a LiCl/LiNO 3 eutectic at 300 ℃, in n-hexanol at 145 ℃, in water at 105 ℃, and in ethanol at 95 ℃. X-ray diffraction indicates that the precursor and ion exchange products have a layered structure with the monoclinic space group \{C2/m\}. Both XRD and ICP analysis demonstrate that temperature influences the rate of the ion exchange reaction and the crystal structure of LiMnO 2 in each case. The higher the temperature, the faster the reaction, and the more severe the distortion of the products. SEM micrographs show that LiMnO 2 possesses a needle-like morphology.