【作者】 赵静；

【导师】 温福昇；

【作者基本信息】 燕山大学 ， 材料学， 2015， 硕士

【摘要】 锂离子电池和钠离子电池作为储能电池对推动各领域技术、经济快速发展的重要性越来越明显,对其性能的要求也不断提高。锡基复合材料以其高的理论容量,成为锂离子电池和钠离子电池研究领域的一个新里程碑。Sn₄P₃中Sn和P对锂和钠都有电化学活性,高电导率的Sn可以改善P的电绝缘性质,而且P元素的存在可以分散Sn颗粒,Sn和P的这种协同作用可以缓解体积膨胀并且阻止电化学团聚。Sn Se以其层状结构和独特的性质在锂离子电池和钠离子电池领域有突出表现。本文利用微波溶剂热法分别制备了Sn₄P₃和Sn Se,为了提高它们的电化学性能,利用该方法分别掺入碳纳米管制备成复合材料。具体研究内容如下:（1）利用微波溶剂热方法分别制备Sn₄P₃和Sn Se以及Sn₄P₃/MWCNTs和Sn Se/MWCNTs复合材料,利用X射线衍射、扫描电子显微镜、透射电子显微镜对其进行定性分析和微观形貌观察。（2）对Sn₄P₃和Sn₄P₃/MWCNTs复合材料锂离子电池和钠离子电池进行了循环伏安测试,研究其储锂和储钠机理,除此之外对其又进行了变电流充放电测试、恒流充放电测试以及交流阻抗测试,研究其循环性能。研究发现,Sn₄P₃/MWCNTs复合材料的循环性能优于Sn₄P₃。锂离子电池测试过程中,当Sn₄P₃/MWCNTs=3/1时,循环稳定性最好,电流密度为500m A/g时,首次放电容量达1506m Ah/g,库伦效率为62%,循环100圈后容量为440m Ah/g;钠离子电池测试过程中,当Sn₄P₃/MWCNTs=1/1时,复合材料的循环稳定性最好,电流密度为200m A/g时,首次放电容量达1092m Ah/g,库伦效率为53%,循环100圈后容量为234m Ah/g。（3）同样对Sn Se和Sn Se/MWCNTs复合材料锂离子电池和钠离子电池进行了循环伏安测试,研究其储锂和储钠机理,除此之外对其又进行了变电流充放电测试、恒流充放电测试以及交流阻抗测试,研究其循环性能。研究发现,在锂离子电池和钠离子电池测试过程中,当Sn Se/MWCNTs=1/2时,复合材料的循环稳定性最好,锂电测试中,当电流密度为100m A/g时,首次放电容量达2244m Ah/g,库伦效率为68%,循环100圈后容量为908m Ah/g;钠电测试中,电流密度为100m A/g时,首次放电容量达1721m Ah/g,库伦效率为50%,循环100圈后容量为366m Ah/g。更多还原

【Abstract】 As the energy storage batteries, the importance of lithium-ion batteries and sodium-ion batteries in promoting technology sectors and speeding up economic development becomes more and more obvious. And the requirements for their performance also increase continuously. Because of its high theoretical capacity, tin-based composite materials have become the new milestone in the study field of lithium-ion batteries and sodium-ion batteries. The Sn and P in Sn₄P₃ have electrochemical activity for both lithium and sodium.The high conductivity of Sn can improve the electrical insulating property of P, and the presence of P can disperse the Sn particles. This synergy of Sn and P can alleviate the volume expansion and prevent electrochemical reunion.The layer structure and unique properties of Sn Se make it behave outstanding in the filed of lithium-ion batteries and sodium-ion batteries.In this paper, Sn₄P₃ and Sn Se were prepared by microwave solvothermal method. In order to improve their electrochemical properties, carbon nanotubes are incorporated into them to prepare the composite materials with the same method.The specific research contents are as follows:（1） The Sn₄P₃, Sn Se,Sn₄P₃/MWCNTs composite and Sn Se/MWCNTs composite are prepared by microwave solvothermal method, respectively. The phases and morphologies of the products were characterized by means of X-ray diffraction（XRD）, scanning electron microscopy（SEM） and transmission electron microscopy（TEM）.（2） The Sn₄P₃ and Sn₄P₃/MWCNTs are set as the anodes for lithium-ion batteries and sodium-ion batteries to study the mechanism of lithium and sodium storage by using cyclic voltammetry. Besides to research their cycle performance, variable current charge-discharge test, the constant current charge-discharge test and AC impedance test are used. The study found that the cycle performance of Sn₄P₃/MWCNTs is better than Sn₄P₃. In the lithium-ion battery testing process, When Sn₄P₃/MWCNTs =3/1, the cycle stability is the best. The Sn₄P₃/MWCNTs =3/1 anode can deliver a initial discharge capacity of 1506 m Ah/g and a coulombic efficiency of 62% at the current density 500 m A/g. After 100 cycles, the capacity is 440 m Ah/g. In the sodium-ion battery testing process, the cycle performance of Sn₄P₃/MWCNTs is also better than Sn₄P₃. When Sn₄P₃/MWCNTs =1/1, the cycle stability is the best. The Sn₄P₃/MWCNTs =1/1 anode can deliver a initial discharge capacity of 1092 m Ah/g and a coulombic efficiency of 53% at the current density 200 m A/g. After 100 cycles, the capacity is 234 m Ah/g.（3） The Sn Se and Sn Se/MWCNTs are set as the anodes for lithium-ion batteries and sodium-ion batteries to study the mechanism of lithium and sodium storage, by using cyclic voltammetry. Besides to research their cycle performance, variable current charge-discharge test, the constant current charge-discharge test and AC impedance test are used. The study found that the cycle performance of Sn Se/MWCNTs is better than Sn Se. In the lithium-ion battery testing process, the Sn Se/MWCNTs =1/2 anode can deliver a initial discharge capacity of 2244 m Ah/g and a coulombic efficiency of 68% at the current density 100 m A/g. After 100 cycles, the capacity is 908 m Ah/g. In the sodium-ion battery testing process, the Sn Se/MWCNTs =1/2 anode can deliver a initial discharge capacity of 1721 m Ah/g and a coulombic efficiency of 50% at the current density 100 m A/g. After 100 cycles, the capacity is 366 m Ah/g.更多还原