Na(+) intercalation pseudocapacitance in graphene-coupled titanium oxide enabling ultra-fast sodium storage and long-term cycling

作     者：Chaoji Chen Yanwei Wen Xianluo Hu Xiulei Ji Mengyu Yan Liqiang Mai Pei Hu Bin Shan Yunhui Huang 

作者机构：State Key Laboratory of Materials Processing and Die &Mould Technology School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China. Department of Chemistry Oregon State University Corvallis Oregon 97331-4003 USA. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing WUT-Harvard Joint Nano Key Laboratory Wuhan University of Technology Wuhan 430070 China. 

出 版 物：《Nature communications》 

年 卷 期：2015年第6卷第1期

页      面：6929页

学科分类：07[理学] 08[工学] 

主　　题：Batteries Electrochemistry Nanocomposites Nanoscience and technology 

摘      要：Sodium-ion batteries are emerging as a highly promising technology for large-scale energy storage applications. However, it remains a significant challenge to develop an anode with superior long-term cycling stability and high-rate capability. Here we demonstrate that the Na(+) intercalation pseudocapacitance in TiO2/graphene nanocomposites enables high-rate capability and long cycle life in a sodium-ion battery. This hybrid electrode exhibits a specific capacity of above 90 mA h g(-1) at 12,000 mA g(-1) (∼36 C). The capacity is highly reversible for more than 4,000 cycles, the longest demonstrated cyclability to date. First-principle calculations demonstrate that the intimate integration of graphene with TiO2 reduces the diffusion energy barrier, thus enhancing the Na(+) intercalation pseudocapacitive process. The Na-ion intercalation pseudocapacitance enabled by tailor-deigned nanostructures represents a promising strategy for developing electrode materials with high power density and long cycle life.