溶胶凝胶法制备网状锰酸锂材料

Preparation of network LiMn_2O_4 by sol-gel method

以乙酸锰和乙酸锂为金属源,间苯二酚和甲醛为分散剂,柠檬酸为络合剂,采用溶胶凝胶法成功制备具有网状结构的锰酸锂粉体.通过XRD、SEM、TEM、循环伏安等测试手段对产物进行了表征,并探究了甲醛的加入量和体系pH对其晶相结构和形貌的影响.实验结果表明:制备的锰酸锂晶粒尺寸在几十个纳米左右,并且当甲醛的加入量为9mL、体系pH为8时,锰酸锂粉体表现出高的纯度、优异的结晶性能以及密集而巨大的面网结构.其循环伏安测试结果表明,其载流子传递、转移方面性能优良,可能因其结晶性能优良,本身所具有的独特的网络结构可以提供更多的嵌锂空间,并且缩短离子扩散路径.

LiMn204 （Lithium manganese oxides） have been synthesized by a sol-gel method u- sing Li（CH3COO） · 2H20 and C4HsMnO4 · 4H20 as metal source, C6H4 （OH）2 and HCHO as the dispersant and citric acid as and chelating agent in the system respectively. The influence of the volume of addition of methanal （HCHO） and pH on the morphology and crystal structure of network LiMn204 powders has been analyzed by means of XRD （X-ray diffraction）, SEM, TEM and cyclic voltammetry techniques. The experimental results show that the main phase of as-prepared pure products is spinel structure, consists of large num- bers of little crystal grains with the diameter of tens of nanometers. When the addition of HCHO is 9 mL and pH 8, the as-prepared LiMn2 04 exhibits high purity, excellent crystalli- zation and obtains huge network structure. The C-V experimental results show that the prod- ucts exhibit an enhanced transmission property of charge carriers, which may due to its ex- cellent crystallization, and its unique network structure maybe provide abundant intercala- tion space and shorten the diffusion path of ions.