Li_(5)FeO_(4)的制备及其在硅碳负极电池体系中补锂性能的研究

Synthesis of Li_(5)FeO_(4)and its pre-lithiation performance in silicon-carbon battery system

以Fe_(2)O_(3)和Li_(2)O为原料,采用高温固相法制备了Li_(5)FeO_(4)材料,并将该材料用作补锂添加剂在三元-硅碳电池体系中进行了补锂性能测试。测试结果表明,合成的Li_(5)FeO_(4)首次脱锂比容量为667.6 mAh/g,可逆比容量仅为1.3 mAh/g,是一种理想的补锂材料。在NCM正极-硅碳负极(750 mAh/g)的全电池体系中分别添加质量分数分别为5%和10%的Li_(5)FeO_(4)时,正极材料的可逆比容量分别为164.8和170.2 mAh/g,相比之下正极中不添加补锂剂时正极可逆比容量仅为142.5 mAh/g。此外,Li_(5)FeO_(4)的加入还可以有效提升电池的循环性能,添加10%Li_(5)FeO_(4)的全电池在300次循环后电池的容量保持率为84.6%,较之未添加补锂剂的电池提升8.3%。

In this paper,Li_(5)FeO_(4)was prepared by solid state method using Fe_(2)O_(3)and Li_(2)O as raw materials.The obtained Li_(5)FeO_(4)was used as lithium supplement additive to test its pre-lithiation capability in NMC/silicon-carbon battery system.The results show that the synthesized Li_(5)FeO_(4)is an ideal lithium supplement material with the charge specific capacity of 667.6 mAh/g and revisable discharge specific capacity of 1.3 mAh/g.Adding 5%Li_(5)FeO_(4)to the full NMC/silicon-carbon(750 mAh/g)battery system,the reversible specific capacity of the cathode material is 164.8 mAh/g,which is further increased to 170.2 mAh/g with the addition of 10%Li_(5)FeO_(4).Moreover,the addition of Li_(5)FeO_(4)can also effectively improve the cycle performance of the battery.The capacity retention rate of the full battery with 10%Li_(5)FeO_(4)addition after 300 cycles is 84.6%,which is 8.3%higher than that of the battery without lithium supplement.