In-situ growth of graphene decorations for high-performance LiFePO4 cathode through solid-state reaction
In-situ growth of graphene decorations for high-performance LiFePO4 cathode through solid-state reaction
复制标题
通过固相反应原位生长高性能LiFePO4阴极石墨烯装饰
DOI：
10.1016/j.jpowsour.2013.10.106
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发表时间：
2014-03-01
影响因子：
9.2
通讯作者：
Zheng, Honghe
中科院分区：
文献类型：
--
作者：
Li, Jing;Zhang, Li;Zheng, Honghe
以葡萄糖为石墨烯原料，以微量FeSO4为催化剂前驱体，采用原位热解和催化石墨化的方法首次合成了石墨烯修饰的LiFePO4复合材料。在750℃的Ar/H-2(95：5)气氛中，FeSO4被热还原为Fe纳米粒子(Fe NPs)，葡萄糖首先裂解为碳碎片，然后在Fe NPs的催化作用下，通过碳碎片的重新排列直接在LiFePO4纳米粒子(LFP NPs)表面原位生长石墨烯片层。石墨烯薄片不仅在LFP纳米颗粒中形成致密而均匀的包覆层，而且在LFP颗粒周围延伸并交联成导电网络。LiFePO_4/石墨烯复合材料在0.1C倍率下表现出高达167.7 mAHg(-1)的可逆比容量，100C倍率放电容量达94.3mAHg(-1)，循环寿命大大延长。这种显著的电化学改善归因于沿LFP表面原位生长的石墨烯涂层和石墨烯网络本质上连接到LFP颗粒而导致的电导率和离子电导率的提高。(C)2013爱思唯尔B.V.保留所有权利。
Graphene-decorated LiFePO4 composite is synthesized for the first time through in-situ pyrolysis and catalytic graphitization, in which glucose and a trace amount of FeSO4 are employed as the graphene source and catalyst precursor, respectively. Under Ar/H-2 (95:5) atmosphere at 750 degrees C, FeSO4 is thermally reduced to Fe nano-particles (Fe NPs) and glucose is pyrolyzed to carbon fragments first, followed by the in-situ growth of graphene sheets directly on the LiFePO4 nano-particles (LFP NPs) surface through the realignment of carbon fragments under the catalytic effect of the Fe NPs. The graphene sheets not only form a compact and uniform coating layer throughout the LFP NPs, but also stretch out and cross-link into a conducting network around the LFP particles. The LiFePO4@graphene composite displays a high reversible specific capacity of 167.7 mAh g(-1) at 0.1C rate, superb rate performance with discharge capacity of 94.3 mAh g(-1) at 100C rate and much prolonged cycle life. The remarkable electrochemical improvement is attributed to both electric and ionic conductivity increase as a result of in-situ grown graphene coatings along the LFP surface and the graphene network intrinsically connecting to the LFP particles. (C) 2013 Elsevier B.V. All rights reserved.