(中南大學(xué) 化學(xué)化工學(xué)院, 長(zhǎng)沙 410083)
摘 要: 采用工業(yè)上常用的碳酸錳熱解法制備錳氧化物前驅(qū)體，與Li2CO3混合后焙燒得到鋰離子電池正極材料LiMn2O4，并在碳酸錳制備過(guò)程中摻入鋁離子制備LiAlxMn2-xO4( x=0.01,0.02,0.03,0.05,0.1)。通過(guò)X射線衍射(XRD)和掃描電鏡(SEM)對(duì)樣品進(jìn)行表征，并對(duì)合成材料在常溫和高溫(55 ℃)下的電化學(xué)性能進(jìn)行研究。結(jié)果表明：合成的前驅(qū)體及錳酸鋰材料均無(wú)雜相；隨著Al3+摻雜量的增加，LiAlxMn2-xO4顆粒尺寸不斷長(zhǎng)大；材料的首次充放電比容量隨Al3+摻雜量的升高而下降，但循環(huán)性能提高；Al3+的摻入極大地提高了材料的循環(huán)性能，尤其是在高溫條件下，當(dāng)摻雜量x=0.05時(shí)， 1C倍率下循環(huán)100次容量的保持率由未摻雜的72.2%升高到90.7%。
關(guān)鍵字: 正極材料；錳酸鋰；摻雜；LiAlxMn2-xO4；循環(huán)性能
（School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China）
Abstract:The spinel LiMn2O4 was synthesized by manganese carbonate pyrolysis method and Al3+ was doped during the MnCO3 synthesis process to get LiAlxMn2-xO4 (x=0.01, 0.02, 0.03, 0.05, 0.1). The samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and their electrochemical performance were tested at room temperature and elevated temperature (55 ℃). The results of MnCO3 and LiMn2O4 have no apparent. With the increase of the doping amounts of Al3+, the particle sizes of LiAlxMn2-xO4 become larger, and the first discharge capacity of LiMn2O4 decrease to some degree. But the LiAlxMn2-xO4 electrode exhibits superior cycling performance. Especially, at elevated temperature (55 ℃), the capacity retention increases from 72.2% for LiMn2O4 to 90.7% for LiAl0.05Mn1.95O4 after 100 cycles at 1C.
Key words: cathode materials; lithium manganate oxide; dope; LiAlxMn2-xO4; cycling performance
