球磨处理尖晶石相LiMn_2O_4的结构及性能

The structure and properties of spinel LiMn_2O_4 with ball-milling treatment

采用球磨促进固相合成法,在500℃合成具有纳米结构的尖晶石相LiMn2O4样品,对样品进行不同时间的球磨处理.并用XRD和FTIR对处理后的样品进行了物相与结构的表征和分析。结果表明,球磨处理使晶体颗粒细化的同时,还引起了晶体颗粒结晶度的降低,造成4.3～3.0V电压区间放电容量减少,而3.0～1.5V电压区间放电容量增大。当球磨处理时间为80h时.尖晶石相LiMn2O4几乎完全非晶化,电化学循环结果表明材料的非晶化能有效地抑制Jahn-Teller效应。

A new method of ball-milling-promoted solid state reaction was used to prepare spinel LiMn2O4 with nanostructure at 500℃ .The spinel LiMn2O4 prepared with above-mentioned method was treated with ball-milling for different time. XRD and FTIR were used to measure the structure of the samples. The results showed that the ball-milling process not only had a refinement effect on the particles but also resulted in the poor crystallinity of samples. The discharge capacity decreased in the range of 4.3~ 3.0V and increased at 3. 0~ 1. 5V. When the time of ball-milling was 80h, spinel LiMn2O4 transformed to amorphous structure completely. The electrochemical cycle life showed that amorphous material had a great effect on depressing the Jahn-Teller effect.