【作者】 王倩；

【导师】 季世军；

【作者基本信息】 大连海事大学 ， 材料科学与工程， 2022， 硕士

【摘要】 锡基材料因其高比容量和中等锂化电位引起了广泛的关注,但其在锂化过程中经历的大体积变化会导致颗粒粉化进而导致容量下降和寿命缩短。研究表明,用多孔碳材料作为结构缓冲不仅可以降低机械应力,还能缩短Li⁺的扩散距离,从而提高锡基材料的电化学性能。在多种碳前驱体中,金属-有机框架（MOFs）是一种新型的多孔晶体材料,由MOFs衍生的碳材料具有比表面积大,孔隙率高等优点。但是MOFs复合材料的制备工艺过于复杂,这带来巨大的能源消耗和成本压力,为此,本文采用三种合成路线:化学镀方法、机械球磨法、溶剂热法,制备出了不同形态的MOFs衍生多孔碳/锡基复合材料,并对这些材料的微观形貌及电化学性能进行了分析,以寻找可低成本、大批量生产高性能碳/锡基锂离子电池负极材料的工艺路线。本文主要研究工作如下:（1）使用化学镀方法合成了SnO₂/C复合材料。对ZIF-8衍生多孔碳的最优热解温度、化学镀工艺参数及镀覆次数进行了系统研究,对比分析确定了最优合成方案。与商业Sn O₂相比,Sn O₂/C复合材料的电化学性能明显提高,分析认为这与多孔碳基体在充放电过程中缓解了Sn O₂的体积膨胀有关。（2）基于高能机械球磨法及随后的热处理制备了ZIF-8衍生碳包覆锡材料。系统研究了球磨时间、金属前驱体与配体的比例、液体辅助研磨剂对产物微观结构和电化学性能的影响。其中球磨90分钟制备的样品表现出最优的循环稳定性,经100次循环后剩余容量仍高达1208 m Ah/g。（3）采用溶剂热法结合煅烧处理制备了ZIF-8衍生的碳/锡复合材料。研究了二次碳源（葡萄糖,尿素,PVP）、溶剂热及煅烧工艺、表面活性剂预处理对产物形貌及性能的影响。研究结果表明,在电流密度为100 m A/g时,SP@C2#复合材料有着63.98%的高初始库伦效率,在100次循环后仍保持在1202 m Ah/g的高容量。（4）综合比较上述几种制备方法,机械球磨法及热处理具有工艺简单、耗时短、适合大批量工业化生产的优点,在锂离子电池负极材料生产中具有潜在的应用前景。更多还原

【Abstract】 Tin-based materials have attracted much attention due to their high specific capacity and moderate lithiation potential,but the large volume change of tin-based materials during lithiation will lead to particle pulverization,which will lead to capacity reduction and life shortening.The research shows that using porous carbon as structural buffer can not only reduce the mechanical stress,but also shorten the diffusion distance of Li⁺,thus improving the electrochemical performance of tin-based materials.Among various carbon precursors,metal-organic frameworks（MOFs）are a new type of porous crystalline material,and carbon materials derived from MOFs have the advantages of large specific surface area and high porosity.However,the preparation process of MOFs composite material is too complicated,which brings huge energy consumption and cost pressure.Therefore,in this thesis,MOFs-derived porous carbon/tin matrix composites are prepared by three synthetic routes:electroless plating method,mechanical ball milling method and solvothermal method and the microstructure and electrochemical properties of these materials are analyzed,in order to find a low-cost and mass production process of high performance carbon/tin matrix lithium ion battery anode materials.The main research works in this thesis are as follows.（1）SnO₂/C composites are synthesized using a electroless plating method.The optimal pyrolysis temperature for ZIF-8-derived porous carbon,electroless plating process parameters and number of plating times are systematically investigated,and the optimal synthesis scheme is determined by comparative analysis.Compared with commercial Sn O₂,the electrochemical performance of the Sn O₂/C composites is significantly improved,which is analyzed to be related to the fact that the porous carbon matrix alleviates the volume expansion of Sn O₂during the charging and discharging process.（2）ZIF-8-derived carbon-coated tin materials are prepared based on high-energy mechanical ball milling method and subsequent heat treatment.The effects of ball milling time,the ratio of metal precursor to ligand and liquid assisted grinding agent on the microstructure and electrochemical properties of the products are systematically studied.Among them,the samples prepared by ball milling for 90 min show the optimal cycling stability,and the residual capacity is still as high as 1208 m Ah/g after 100 cycles.（3）ZIF-8-derived carbon/tin composites are prepared by a solvothermal method combined with calcination treatment.The effects of secondary carbon source（glucose,urea,PVP）,solvothermal and calcination process,and surfactant pretreatment on the morphology and properties of the products are investigated.It is found that SP@C2#composites has a high initial Coulombic efficiency of 63.98%at a current density of 100 m A/g,remaining at1202 m Ah/g after 100 cycles.（4）By comprehensive comparison of the above preparation methods,the mechanical ball milling method and heat treatment have the advantages of simple process,short time consumption and suitable for mass industrial production,which have potential application prospect in the production of anode materials for lithium-ion batteries.更多还原