过渡金属掺杂的锂电池正极材料研究

发布时间：2018-11-24 18:31

【摘要】：LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2正极材料由于其较高的可逆容量、稳定的结构、较强的热稳定性和相对较低的成本,已经被很多研究人员进行了深入广泛的研究。然而,研究人员对过渡金属氧化物电极材料进行了更彻底的研究,发现经过多次的充放电后其循环稳定性能逐渐变差。此外,LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2锂电池的快速容量衰减和低速率能力也是阻碍其在高功率应用中可持续性和使用性的主要问题。在本论文中,我们首先讨论两种过渡金属掺杂的电极材料和它们的电化学性能。LiNi_(1/3)Cu_xCo_(1/3-x_Mn_(1/3)O_2和LiFe_xNi_(1/3-x)Co_(1/3)Mn_(1/3)O_2(0.000≤x≤0.267)两种微球材料分别按化学计量利用铜掺杂替代钴和铁替代掺杂镍进行合成。由于在铜掺杂材料中出现了颗粒的团聚和产生了杂质相,导致比容量的降低。适量的铁掺杂材料可以提高锂离子电池的比容量。以MnO2微球为模板,用Zn掺杂三元系LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2材料,合成LiNi_(1/3)Zn_xCo_(1/3-x)Mn_(1/3)O_2(0.000≤x≤0.133)微球材料。一个空心微球颗粒的直径大约为4微米,它又有大量300纳米的小微粒组成。利用RIETAN-FP软件对样品进行XRD结构解析,得出样品具有α-NaFeO_2层状结构。然后组成锂离子纽扣电池,在2.5V到4.5 V的电压范围内进行电化学性能测试。通过测试,发现随着锌掺杂浓度的增加,锂电池的循环性能和倍率性能同材料的晶格参数具有相似的变化趋势。掺杂量x=0.133的样品比其它样品具有更好的电化学性能,与没掺杂锌的材料比较,其锂电池比容量增加了10.7%。此外,LiNi_(1/3)Zn_xCo_(1/3-x)Mn_(1/3)O_2(x=0.133)空心微球材料的松散、多孔结构有利于锂离子在电极材料内的迁移,并且可以储存电解液,进一步增强锂离子的扩散和电荷转移。
[Abstract]:LiNi_ (1 / 3) Co_ (1 / 3) Mn_ (1 / 3) O _ 2 cathode material, due to its high reversible capacity, stable structure, strong thermal stability and relatively low cost, It has been extensively studied by many researchers. However, the researchers conducted a more thorough study of transition metal oxide electrode materials, and found that the cyclic stability of transition metal oxide electrode materials became worse after repeated charge and discharge. In addition, the rapid capacity attenuation and low rate capability of LiNi_ (1 / 3) Co_ (1 / 3) Mn_ (1 / 3) O _ 2 lithium battery are also the main problems that hinder its sustainability and usability in high-power applications. In this paper, We first discuss two transition metal-doped electrode materials and their electrochemical properties. LiNi_ (1 / 3) Cu_xCo_ (1 / 3-xMn_ (1 / 3) O _ 2 and LiFe_xNi_ (1 / 3-x) Co) Two kinds of Mn_ (1 / 3) O _ 2 (0.000 鈮，

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