(中南大學(xué) 冶金科學(xué)與工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 通過X射線衍射(XRD)、掃描電鏡(SEM)、粒度分析以及充放電性能測(cè)試對(duì)固相燒結(jié)法制備的LiCoxMn2−xO4(x=0，0.05，0.10，0.15，0.20)結(jié)構(gòu)、形貌進(jìn)行表征，并對(duì)電化學(xué)性質(zhì)進(jìn)行研究。研究結(jié)果表明，LiCoxMn2−xO4(x=0，0.05，0.10，0.15，0.20)均為單一尖晶石結(jié)構(gòu)，無雜相存在；晶格常數(shù)隨著摻雜量x的增大而線性減小；鈷摻雜有助于LiCoxMn2−xO4晶體更規(guī)則地生長(zhǎng)，使一次顆粒呈現(xiàn)八面體結(jié)構(gòu)；摻鈷對(duì)LiCoxMn2−xO4的平均粒徑無明顯影響；純LiMn2O4在循環(huán)過種中容量衰減快，鈷摻雜明顯地改善了LiMn2O4充放電循環(huán)性能，且大電流放電能力提高；隨著摻鈷量的提高，大電流充放電性能與循環(huán)過程中容量的保持率也提高。
關(guān)鍵字: 鋰離子電池；錳酸鋰；尖晶石；鈷摻雜；正極材料
Co-doping lithium manganese oxide
（School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Properties of LiCoxMn2−xO4(x=0, 0.05, 0.10, 0.15, 0.20) synthesized by solid state reaction were studied in the aspects of structure, and electrochemistry using X-ray diffractometry(XRD), scanning electronic microscopy(SEM), distribution of particle size and charge-discharge measurement. The results show that the pure phase exists with the same structure as spinel to all samples with and without cobalt-doping, not containing other minor impurity. The linear relationship of lattice parameter and Co-doping amount for LiCoxMn2−xO4 is determined by powder XRD refinement. The more regular octahedral morphology of primary particles is observed under scanning electron microscope, which indicates the doping of cobalt is beneficial to the growth of crystal. However, the particle size is not affected by cobalt doping. The cycleability and the rate capability are greatly improved by the introduction of cobalt to the lattice. The more the amount of manganese is substituted by cobalt, the higher the capacity retention and more excellent rate capability are obtained.
Key words: lithium ion batteries; lithium manganese oxide; spinel; cobalt doping; cathode materials
