Additive-free solvothermal synthesis of hierarchical flower-like LiFePO4/C mesocrystal and its electrochemical performance
Additive-free solvothermal synthesis of hierarchical flower-like LiFePO4/C mesocrystal and its electrochemical performance
复制标题
DOI：
10.1039/c3ra42855a
复制
发表时间：
2013-10
期刊：
影响因子：
3.9
通讯作者：
Nan Zhou;Nan Zhou;Nan Zhou;E. Uchaker;Hai-yan Wang;M. Zhang;Suqin Liu;You-nian Liu;Xiongwei Wu-Xi
中科院分区：
文献类型：
--
作者：
Nan Zhou;Nan Zhou;Nan Zhou;E. Uchaker;Hai-yan Wang;M. Zhang;Suqin Liu;You-nian Liu;Xiongwei Wu-Xi
以水/乙二醇/二甲基乙酰胺（H2O/EG/DMAC）为共溶剂，采用溶剂热法成功合成了具有三维层次结构的花状磷酸铁锂（LiFePO 4）介晶.在不使用其他表面活性剂或模板剂的情况下，得到了具有特殊玫瑰状形貌的美丽的微米级LiFePO 4介孔结构。采用纳米尺度的LiFePO 4薄片组装成LiFePO 4介晶，厚度约为100 nm。对所制备的多级花状LiFePO 4介晶的特性、电化学动力学和性能进行了研究。花状分级LiFePO 4介晶在17 mA g-1（0.1 C）的电流密度下显示出147 mA h g-1的高初始嵌锂能力，这应归因于由介孔超结构和良好结晶的LiFePO 4纳米片组合物单元产生的高比表面积。在溶剂热合成过程中引入聚乙烯吡咯烷酮（PVP）作为原位碳涂层源。得到的花状C包覆LiFePO 4介晶在0.1 C下表现出161 mA h g-1的甚至更好的初始嵌锂能力，并且表现出改善的高速率下的锂储存性能以及良好的循环稳定性。
Three dimensional hierarchical flower-like lithium iron phosphate (LiFePO4) mesocrystals were successfully synthesized via a solvothermal approach with the utilization of a mixture of water/ethylene glycol/dimethylacetamide (H2O/EG/DMAC) as co-solvent. No other surfactant or template agent was used and beautiful micro-sized LiFePO4 mesoporous structures with a special rose-like morphology were obtained. The hierarchical LiFePO4 mesocrystals were assembled by well crystallized nano-sized LiFePO4 thin plates with a thickness around 100 nm. The characteristics and electrochemical dynamics as well as performance of the obtained hierarchical flower-like LiFePO4 mesocrystals were carefully investigated. The flower-like hierarchical LiFePO4 mesocrystals showed a high initial lithium intercalation capability of 147 mA h g−1 at a current density of 17 mA g−1 (0.1 C), which should be attributed to the high specific surface area resulting from the mesoporous superstructure and well crystallized LiFePO4 nano-plate composition units. Polyvinylpyrrolidone (PVP) was introduced during the solvothermal synthesis as an in situ carbon coating source. The obtained flower-like C-coated LiFePO4 mesocrystals exhibited even better initial lithium intercalation capability of 161 mA h g−1 at 0.1 C and showed improved lithium storage performance at high rates as well as good cyclic stability.