Preparation And Application Of Transition Metal Compounds In Lithium Sulfur Batteries

Currently,the energy density of commercial lithium-ion batteries are difficult to meet the development of portable electronic devices and electric vehicles.Due to the high theoretical specific energy（2600 Wh/kg）,low cost and environmental friendliness,lithium-sulfur batteries are considered the most promising next-generation energy storage systems.However,the low special capacity and poor cycling stability limit their further development,which can be attributed to the poor conductivity of sulfur and the shuttle of lithium polysulfide.Based on these issues,some new conductive matrix materials that can improve the specific capacity,rate performance and cycling stability of Li-S batteries have been developed in this paper,such as carbon/（transition metal oxides,sulfides,nitrides,etc.）The main results are as follows:（1）Preparation the carbon/LiTi₂（PO₄）_2.88F_0.12 composite as a sulfur host using sol-gel method,which exhibits higher specific capacity（about 200 mAh/g）due to its high ion conductivity;（2）Construction the carbon/NiCo₂S₄ composite with hollow structure using kirkendall effect,which shows excellent rate performance（capacity is 580 mAh/g at 5 C）;（3）Carbon/Fe₃O₄@C composite is prepared using MIL-53 as a template,which delivers excellent cycling stability（capacity decay rate is 0.002%after 300 cycles at 1 C）;（4）PB derived carbon/FeN₃@C composite acts as a sulfur host,which exhibits high specific capacity of 690 mAh/g and excellent cycling stability at 1 C（the capacity retention is 86%after 500 cycles）;...