表面Ti掺杂对锂离子电池正极材料Li_1.2Mn_0.54Ni_0.13Co_0.13O₂的改性研究

【摘要】 高能量密度是消费电子产品和电动汽车用的锂离子电池最重要的指标之一。为了提高锂离子电池能量密度和循环性能,提高和改善正极材料的性能是非常重要的。目前,富锂层状结构的氧化物材料被认为是最有前途的正极材料。然而,对于实际应用来说,这类材料仍旧存在严重的问题,包括:随着充放电循环的进行,首次循环不可逆容量损失较高,电池容量连续衰退,电压下降较快等。本研究通过表面改性技术,对富锂正极材料Li_1.2Mn_0.54Ni_0.13Co_0.13O₂(或写为Li₂MnO₃·LiNi_1/3Co_1/3Mn_1/3O₂,简称为LMRO)的表面层掺杂Ti,大大改善了材料的品质和性能。电化学测试结果表明表面掺杂Ti元素的LMRO保持了275mAh/g的高容量（保持率93%）,在50次充放电循环后,电池电压仅仅下降了0.29V（保持率92%）。我们并对其中品质改善的机理做了一些探讨。更多还原

【Abstract】 High energy density is one of the most important indicator of lithium-ion batteries for consumer electronics and electric vehicles. In order to improve the energy density and cycle performance of lithium ion batteries, it is very important to improve the performance of cathode materials. At present, lithium-rich layered oxide materials are considered as the most promising cathode materials. However, for practical applications, there are still serious problems, including: with the charge-discharge cycle, the irreversible capacity loss of the first cycle is higher, the capacity of battery continues to decline, the voltage drops quickly and so on. In this study, Ti was doped into the surface layer of lithium-rich cathode material Li_1.2Mn_0.54Ni_0.13Co_0.13O₂(or Li₂MnO₃·LiNi_1/3Co_1/3Mn_1/3O₂, referred to as LMRO) by surface modification, which greatly improved the quality and performance of the battery. The results of electrochemical measurements show that the Ti-doped LMRO Ti maintains a high capacity of 275 mAh/g（retention 93%）. After 50 charge-discharge cycles, the cell voltage decreases by only 0.29 V（retention 92%）. The mechanism of performance improvement has been discussed.更多还原