Tetragonal structured LiMnO _(2) (t-LiMnO _(2) ) samples were synthesized under pressures above 8 GPa and investigated as a positive electrode material for lithium-ion batteries. Rietveld analyses based on X-ray diffraction measurements indicated that t-LiMnO _(2) belongs to a γ-LiFeO _(2) -type crystal structure with the I 4 _(1) / amd space group. The charge capacity during the initial cycle was 37 mA h g ~(?1) at 25 °C, but improved to 185 mA h g ~(?1) at 40 °C with an average voltage of 4.56 V vs. Li ~(+) /Li. This demonstrated the superiority of t-LiMnO _(2) over other lithium manganese oxides in terms of energy density. The X-ray diffraction measurements and Raman spectroscopy of cycled t-LiMnO _(2) indicated an irreversible transformation from the γ-LiFeO _(2) -type structure into a Li _( x ) Mn _(2) O _(4) spinel structure by the displacement of 25% of the Mn ions to vacant octahedral sites through adjacent octahedral sites.
展开▼
机译：在高于8 GPa的压力下合成四方结构的LiMnO _（2）（t-LiMnO _（2））样品，并将其用作锂离子电池的正极材料。基于X射线衍射测量的Rietveld分析表明，t-LiMnO_（2）属于具有I 4_（1）/ amd空间群的γ-LiFeO_（（2））型晶体结构。初始循环中的充电容量在25°C时为37 mA hg〜（？1），但在40°C时提高到185 mA hg〜（？1），平均电压为4.56 V vs. Li〜（+） /李这证明了在能量密度方面，t-LiMnO_（2）优于其他锂锰氧化物。循环t-LiMnO _（2）的X射线衍射测量和拉曼光谱表明从γ-LiFeO_（2）型结构不可逆转变为Li _（x）Mn _（2）O _（4 ）通过将25％的Mn离子通过相邻的八面体位点转移到空的八面体位点来形成尖晶石结构。
展开▼
