锂离子筛前驱体Li_4Mn_5O_(12)的制备及性能

Synthesis and properties of lithium ion-sieve precursor Li_4Mn_5O_(12)

以水热法自制γ-MnOOH和LiOH·H2O为原料,在较低温度下固相反应制备出尖晶石型Li4Mn5O12,经酸浸脱锂后得到对Li+具有特殊选择性的MnO2离子筛。研究该离子筛对Li+的吸附性能和选择性,并用XRD、SEM和FT-IR等和Li+选择性吸附研究固相反应工艺对离子筛材料结构、化学组成及离子交换性质的影响。结果表明:煅烧时间对前驱体的生成有较大影响,由400℃煅烧32 h所得的前驱体为纯相Li4Mn5O12化合物,经酸浸脱锂后的离子筛仍保持与前驱体相同的尖晶石结构;锰源γ-MnOOH、前驱体Li4Mn5O12和离子筛MnO2均为低维棒状结构形貌;离子筛对锂的吸附速率符合一级动力学Lagergren方程,饱和吸附容量为40.2 mg/g,并具有较好的Li+选择性。

Spinel-type Li4MnsO12 precursors were synthesized from ？-MnOOH self-prepared by hydro-thermal method and LiOH＇HzO by low temperature solid-phase reaction. Furthermore, MnO2 ion-sieves with Li＋ selective adsorption property were prepared by the acid treatment process to extract Li＋ from the spinel Li4Mn5O12 precursor. The effects of solid-phase reaction process on the structure, chemical composition and ion-exchange property of the ion-sieve material were investigated by XRD, SEM, FT-IR and Li＋ selective adsorption measurements. The results show that calcination time has the considerable effect on the precursor. The precursor synthesized at 400 ＊C for 32 h is a pure Li4Mn5012. Final MnO2 ion-sieve and LiaMn5Ol2 precursor have a low-dimensional rod-like morphology link ？-MnOOH and share the same structure of spinel. The adsorption rate of ion-sieve is consistent with the pseudo-first order kinetic equation of Lagergren. The Li＋ saturated adsorption capacity is 40.2 mg/g, and the ion-sieve shows good Li＋ selection.