本文選題：鋰離子電池 + 負極材料��； 參考：《華南理工大學》2014年碩士論文

【摘要】：本論文針對金屬基鍺類負極材料在應用過程中雖表現(xiàn)出較高的首次充放電比容量，但隨后循環(huán)中所遭遇較快容量衰減的問題，運用了水熱合成法、固相合成法兩種方法分別合成了具有新型結(jié)構(gòu)的納米鍺酸銅、鍺酸鋅負極材料，并分別將其與石墨烯和石墨進行復合。利用XRD、SEM、TEM、XPS、Raman等技術(shù)對這些材料的組成以及微觀形貌進行表征，采用循環(huán)伏安法（CV）、電化學阻抗（EIS）和恒電流充放電等技術(shù)測試了各種復合材料的電性能。本論文主要開展了以下幾方面的工作： 利用六角晶型結(jié)構(gòu)的GeO2能夠微溶于水的性質(zhì)，將其與乙酸銅反應，成功制得了具有納米線結(jié)構(gòu)的鍺酸銅，為進一步穩(wěn)定其性能，在其制備過程中又加入了氧化石墨烯溶液，水熱反應后制得了CuGeO3/石墨烯復合負極材料。該材料中石墨烯含量為37%的樣品在200mA/g的電流密度下，首次可逆比容量高達1265mAh/g，，庫倫效率達71.6%，隨后每次循環(huán)中，庫倫效率均接近100%，經(jīng)過50周循環(huán)后，材料的可逆比容量仍保持為853mAh/g。 使用兩步水熱合成法成功制得納米棒結(jié)構(gòu)的Zn2GeO4與石墨烯的復合材料，并且合成了部分結(jié)晶的Zn2GeO4納米棒并將其應用到負極材料中。復合材料中石墨烯的含量僅為10wt%左右，而在后續(xù)的大電流密度（0.8A/g）下循環(huán)時，仍舊表現(xiàn)出了十分穩(wěn)定的電性能（循環(huán)50周，可逆比容量為514mAh/g）。在所有的循環(huán)以及倍率測試中，復合材料所表現(xiàn)出的庫倫效率均接近于100%。考慮到材料的工業(yè)化用途，本實驗采用固相合成法在1000℃下合成Zn2GeO4材料， 后續(xù)使用簡單的球磨法將石墨與Zn2GeO4按照不同的比例進行混合以獲取復合材料。該種復合材料能夠在較大的電流密度下保持很好的循環(huán)性能，改善了石墨在大電流下循環(huán)時容量衰減較快的問題。最終得出，當Zn2GeO4的含量為20%時，復合材料得到最好的循環(huán)性能，并且循環(huán)50周后其可逆比容量接近于500mAh/g。
[Abstract]:In this paper, the hydrothermal synthesis method is used to solve the problem that the metal-based germanium anode material has a high first charge / discharge specific capacity, but the rapid capacity decay in the subsequent cycle, although the first charge / discharge specific capacity of the metal based germanium anode material is high. Nanocrystalline copper germanate and zinc germanate anode materials with novel structures were synthesized by solid state synthesis method and combined with graphene and graphite respectively. The composition and micromorphology of these composites were characterized by XRDX SEMX TM Tem Raman technique. The electrical properties of the composites were measured by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and constant current charge / discharge (CCS) techniques. The main work of this thesis is as follows: Copper germanate with nanowire structure was successfully prepared by using the water-soluble properties of hexagonal GeO2, which was reacted with copper acetate. In order to further stabilize its properties, graphene oxide solution was added in the preparation process. CuGeO3/ graphene composite anode material was prepared by hydrothermal reaction. Under the current density of 200mA/g, the first reversible specific capacity of the sample with 37% graphene content is 1265mAh/ g, and the Coulomb efficiency is 71.6g. In each cycle thereafter, the Coulomb efficiency is close to 100mg. After 50 weeks of cycle, the reversible specific capacity of the material remains at 853mAh.g. The composites of Zn2GeO4 and graphene with nanorod structure were successfully prepared by two-step hydrothermal synthesis, and partially crystallized Zn2GeO4 nanorods were synthesized and applied to negative electrode materials. The content of graphene in the composite is only about 10 wt%, but it still shows a very stable electrical property (the reversible specific capacity is 514 mg 路h / g) at the subsequent cycle with high current density (0.8 A / g). The Coulomb efficiency of the composite is close to 100 in all cycle and rate tests. Considering the industrial use of the materials, Zn2GeO4 materials were synthesized by solid state synthesis at 1000 鈩

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