In-situ synthesizing superior high-rate LiFePO4/C nanorods embedded in graphene matrix
In-situ synthesizing superior high-rate LiFePO4/C nanorods embedded in graphene matrix
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DOI：
10.1016/j.electacta.2013.11.106
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发表时间：
2014-01
影响因子：
6.6
通讯作者：
Yu Long;Ye Shu;Xiaohua Ma;Minxing Ye
中科院分区：
文献类型：
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作者：
Yu Long;Ye Shu;Xiaohua Ma;Minxing Ye
为了克服传统碳基添加剂对LiFePO 4振实密度和体积能量密度的不利影响，通过水热合成、热处理和用上级导电石墨烯纳米片替代传统碳，成功制备了C-LiFePO 4/石墨烯。在乙二醇/水混合介质中，氧化石墨的还原和LiFePO 4的合成同时进行，有利于LiFePO 4颗粒和石墨烯纳米片的相容性和结构。由于薄碳包覆层和低组分石墨烯基体在优势互补基础上的协同作用，使得C-LiFePO 4/graphene具有上级高倍率性能和良好的能量密度，其独特的结构和几何特征是LiFePO 4/C纳米棒嵌入石墨烯纳米片交织而成的基体中。双涂层对电子电导率和锂离子传输产生显著的能量影响，因此新型复合材料呈现出优异的电化学性能，其在20 C下的可逆容量为100 mAh/g，在50 C下为80 mAh/g，同时保持1.76 g/cm 3的高振实密度。
To overcome the detrimental effects of LiFePO4on the tap density and volumetric energy density accompanied by conventional carbon-based additives, C-LiFePO4/graphene was successfully prepared via hydrothermal synthesis, followed by heat treatment, and by substitution of superior conductive graphene nanosheets for some conventional carbon. The reduction of graphite oxide and the synthesis of LiFePO4were carried out simultaneously in mixed ethylene glycol/water medium, facilitating desirable compatibility and architecture of LiFePO4particles and graphene nanosheets. Due to the synergism of thin carbon coating and graphene matrix with low fraction on the basis of complementary advantages, C-LiFePO4/graphene exhibits superior high-rate performance and favorable energy density, which with a unique structural and geometrical feature that LiFePO4/C nanorods embedded in a matrix built of interweaved graphene nanosheets. The dual coatings exert a significantly energetic impact on the electronic conductivity and lithium ion transport, thus novel composite presented excellent electrochemical properties, which was achieved with reversible capacities of 100 mAh/g at 20 C and 80 mAh/g at 50 C, while preserving a high tap density of 1.76 g/cm3.