LiMn_2O_4纳米晶的低温水热前驱体法合成与表征

Synthesis and Characterization of Nanocrystalline LiMn_2O_4 by Hydrothermal Precursor Method with Low Temperature

LiMn2O4由于电压高、价格便宜、对环境基本无污染而成为最有希望的备选正极材料之一.大量实验研究表明,制备方法和制备条件的不同会在很大程度上影响LiMn2O4材料的性能.以Mn(CH3COO)2.4H2O和Na2S2O8为原料,采用低温水热法制得纳米晶前驱体β-MnO2粉末,然后将前驱体β-MnO2粉末与LiOH.H2O混合后煅烧即可制得纳米晶LiMn2O4.结果表明,LiMn2O4粉末晶化程度高,粒度分布较窄,平均粒径约在250,nm,用所得的粉末样品进行电化学性能侧试,其首次放电比容量可达130.5,mA.h/g,循环性能也较好.

LiMn204 is one of the most promising cathode materials for its high voltage, low cost and non-pollution to the environment. The quality of LiMn204 powers strongly depends on the synthesis methods and conditions. The main purpose of this paper was to explore the best method for the LiMn204 synthesis. The nanometer precursor fl-MnO2 was produced through the hydrothermal reaction with low temperature using Mn （CH3COO） 2＇4H20 and Na2S208. Then the nanometer precursor fl-MnO2 and LiOH＇H20 were mixed together in order to be calcined to synthesize the nanometer LiMn204. The result shows that nanometer LiMn204 powders have a high degree of crystallization, stable crystal structures, and ultrafine particles with 250 nm in average size. The as-synthesized products have been measured as cathode materials with good electrochemical properties. The first discharge capacity of the cathode was 130.5 mA.h/ g, and the specific capacity after many cycles of this material was excellent.