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以己二酸为配位体采用溶胶-凝胶法合成了LiMn_2O_4,Mg掺杂或Mg和F复合掺杂的尖晶石锂镁氧化物正极材料。对合成出的样品采用X-射线衍射仪、X-光电子能谱、扫描显微电子镜、循环伏安测试和充放电测试仪进行了详细的研究。X-射线衍射结果表明,所有的样品都具有相同的纯尖晶石相,LiMg_(0.1)Mn_(1.9)O_4和LiMg_(0.1)Mn_(1.9)O_(3.95)F_(0.05)与LiMn_2O_4的样品相比,具有较小的晶格参数和晶胞体积。X-光电子能谱试验结果表明,在LiMn_2O_4中,Mn~(3+)和Mn~(4+)的相对量分别为50.2%和49.8%,而LiMg_(0.1)Mn_(1.9)O_(3.95)F_(0.05)中Mn~(3+)和Mn~(4+)的相对量分别为48.4%和51.6%。扫描电镜结果显示,LiMg_(0.1)Mn_(1.9)O_(3.95)F_(0.05)颗粒尺寸略小、尺寸分布窄,形态结构更为规整。循环伏安实验显示,Mg和F复合掺杂的尖晶石具有更好的可逆性。LiMn_2O_4,LiMg_(0.1)Mn_(1.9)O_4,LiMg_(0.1)Mn_(1.9)O_(3.95)F_(0.05)样品的首次放电能量和能量保持率分别为123、111、114 mAh·g~(-1)和86.5%、92.3%、90.9%,且LiMg_(0.1)Mn_(1.9)O_4和LiMg_(0.1)Mn_(1.9)O_(3.95)F_(0.05)具有比LiMn_2O_4更高的库仑效率。
LiMn2O4, Mg doped or Mg and F doped spinel lithium-magnesium oxide cathode material was synthesized by sol-gel method using adipic acid as ligand. The synthesized samples were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, cyclic voltammetry and charge-discharge tester. X-ray diffraction results show that all the samples have the same pure spinel phase, the samples of LiMg_ (0.1) Mn_ (1.9) O_4 and LiMg_ (0.1) Mn_ (1.9) O_ (3.95) F_ (0.05) and LiMn_2O_4 Compared with smaller lattice parameters and unit cell volume. The results of X-ray photoelectron spectroscopy showed that the relative amounts of Mn 3+ and Mn 4+ in LiMn 2 O 4 were 50.2% and 49.8%, respectively, while those of LiMg 0.1 Mn 1.9 O 3 3.95, The relative amounts of Mn ~ (3+) and Mn ~ (4+) in F_ (0.05) were 48.4% and 51.6%, respectively. Scanning electron microscopy results showed that the particle size of LiMg_ (0.1) Mn_ (1.9) O_ (3.95) F_ (0.05) is slightly smaller, the size distribution is narrower and the morphology is more regular. Cyclic voltammetry experiments show that Mg and F composite doped spinel has better reversibility. The first discharge energies and energy retention rates of LiMn2O4, LiMg_ (0.1) Mn_ (1.9) O_4, LiMg_ (0.1) Mn_ (1.9) O_ (3.95) F_ (0.05) samples were 123,111,114 mAh · g ~ LiMg_ (0.1) Mn_ (1.9) O_4 and LiMg_ (0.1) Mn_ (1.9) O_ (3.95) F_ (0.05) have higher Coulombic efficiencies than LiMn_2O_4.