本文使用FeCl3·6H2O作为铁源，Ni(NO3)3·6H2O作为镍源，C8H6O4作为有机配体，C3H7NO作为溶剂，通过一步简单溶剂热法，得到了正八面体的Fe-MIL-88和梭形的Fe-MIL-101两种形貌完全不同的金属-有机框架结构。将得到的样品与锂盐和硅酸盐在乙醇中混合搅拌。蒸发溶剂后，得到的干燥样品经过高温煅烧制得最终产物LiFeSi/C和LiFeNiSi/C。

将材料制成半电池，测试其作为锂离子电池正极材料的电化学性能。在0.1C的电流密度下进行30次循环后，该LiFeSi/C的可逆充放电容量达到155mAhg-1（理论容量为160mAhg-1）。这个材料同时也具有良好的倍率性能，即使在5C的大电流密度下，LiFeSi/C仍有80mAhg-1的可逆容量。此结果表明，多孔碳源包覆的特殊结构可以提供快速的锂离子通道和稳定的结构，这有助于提升锂过渡金属硅酸盐的储锂性能。对LiFeSi/C进行镍掺杂得到的LiFeNiSi/C而言，虽然可逆充放电容量稍微有些降低，达到130mAhg-1，但Ni掺杂的LiFeNiSi/C材料的循环性能，库伦效率，倍率性能，以及电子离子传导率得到了明显的提升。

关键词 MOFs 锂过渡金属原子硅酸盐 锂离子电池 正极材料

毕业设计说明书外文摘要

Title  Study on Preparation  and Lithium  - storage properties of MOF  supported iron  electrode materials  

Abstract：In this paper, Fe-MIL-88 and Fe-MIL-101 with different morphologies were successfully prepared via a simple solvothermal method, in which FeCl3·6H2O as Fe source, Ni(NO3)3·6H2O as Ni source, C8H6O4   as organic ligand and C3H7NO  as solvent. After that,  the resulting  samples were mixed and stirred with lithium salt and silicate in ethanol. After evaporation of the solvent, the resulting samples were calcined at high temperature to produce the final products LiFeSi/C and LiFeNiSi/C.

The electrochemical properties of the materials as the cathode material were systematically studied by assembling half-cells. After 30 cycles at a current density of 0.1C, the LiFeSi/C displays a stable reversible capacity of 155 mAh g-1(the  theoretical capacity is 160 mAh g-1) and a good rate performance, even in a high current density 5C, LiFeSi/C still displays charging and discharging capacity of 80 mAh g-1. The results show that the specific structure of mesoporous carbon coated Li2FeSiO4 is helpful to enhance the lithium storage properties, by providing quick lithium ions/electron pathway and stable structure. As for Ni-doped sample, the capacity slightly reduced to 130 mAh g-1. However, the cyclic and rate performance, Coulomb efficiency, and electron conductivity of LiFeNiSi/C material have been improved obviously.

Keywords MOFs Lithium  transition-metal orthosilicates Lithium  Ion Battery Cathode material 

1 引言 1

1.1 锂离子电池简介 1

1.1.1 锂离子电池的结构和工作原理 1

1.2 锂过渡金属原子硅酸盐概述 3

1.2.1 锂过渡金属原子硅酸盐作为正极材料的改善方法 3

1.3 金属-有机框架材料概述