Al-Mg共掺杂钴酸锂的合成及其电化学性能研究

Synthesis and electrochemical properties of Al-Mg co-doped lithium cobalt oxide

钴酸锂(LCO)作为锂电池正极材料,在电子产品领域有非常广泛的应用,但由于高电压下会导致其晶相的不可逆相变从而导致循环稳定性降低,因此如何提高钴酸锂在高电压下的电化学稳定性一直是研究热点。为了改善钴酸锂的电化学稳定性,采用固相球磨-烧结法合成了Al-Mg共掺杂的LCO材料。采用X射线衍射(XRD)和扫描电镜(SEM)及电化学性能测试表征晶体结构、形貌和测量其循环稳定性。结果表明:Mg、Al进入钴酸锂晶格内部后有效地提高了其电化学稳定性,当Al掺杂量为0.1%,Mg掺杂量为1%时,在0.5C的倍率,3~4.5V的电压下,首圈放电比容量可达136.7mAh/g,100圈后的容量保持率可达76.2%,同时也表现出了良好的倍率性能。

Lithium cobalt oxide(LCO),as a cathode material for lithium batteries,has a very wide range of applications in the field of electronic products,but how to improve the electrochemical stability of LCO at high voltage has been a research hotspot because high voltage can lead to the irreversible phase transition of its crystalline phase and thus lead to the reduction of cycling stability.In order to improve the electrochemical stability of LCO,Al-Mg co-doped LCO material was synthesized by solid-phase ball-milling-sintering method.X-ray diffraction(XRD) and scanning electron microscopy(SEM) as well as electrochemical property tests were used to characterize the crystal structure,morphology and measure its cycling stability.The results showed that the entry of Mg and Al into the interior of the LCO lattice effectively improved its electrochemical stability.When the Al doping amount was 0.1% and the Mg doping amount was 1%,the specific capacity of the first cycle discharge could reach 136.7mAh/g at a multiplicity of 0.5C and a voltage of 3~4.5V.The capacity retention after 100 cycles remained at 76.2%,and it also exhibited a good multiplicity performance.