Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission & Ministry of Education, College of Chemistry and Materials Science, South-Central University for Nationalities , Wuhan, 430074, P. R. China.
College of Chemistry and Molecular Sciences, Wuhan University , Wuhan 430072, China.
ACS Appl Mater Interfaces. 2017 Jun 14;9(23):19900-19907. doi: 10.1021/acsami.7b04407. Epub 2017 Jun 1.
Electrochemical conversion reactions of metal oxides provide a new avenue to build high capacity anodes for sodium-ion batteries. However, the poor rate performance and cyclability of these conversion anodes remain a significant challenge for Na-ion battery applications because most of the conversion anodes suffer from sluggish kinetics and irreversible structural change during cycles. In this paper, we report an FeO single crystallites/reduced graphene oxide composite (FeO/rGO), where the FeO single crystallites with a particle size of ∼300 nm were uniformly anchored on the rGO nanosheets, which provide a highly conductive framework to facilitate electron transport and a flexible matrix to buffer the volume change of the material during cycling. This FeO/rGO composite anode shows a very high reversible capacity of 610 mAh g at 50 mA g, a high Coulombic efficiency of 71% at the first cycle, and a strong cyclability with 82% capacity retention after 100 cycles, suggesting a potential feasibility for sodium-ion batteries. More significantly, the present work clearly illustrates that an electrochemical conversion anode can be made with high capacity utilization, strong rate capability, and stable cyclability through appropriately tailoring the lattice structure, particle size, and electronic conduction channels for a simple transition-metal oxide, thus offering abundant selections for development of low-cost and high-performance Na-storage electrodes.
金属氧化物的电化学转化反应为构建高容量钠离子电池提供了新途径。然而，这些转化阳极的差倍率性能和循环稳定性仍然是钠离子电池应用的一个重大挑战，因为大多数转化阳极在循环过程中遭受缓慢的动力学和不可逆的结构变化。在本文中，我们报告了一种 FeO 单晶/还原氧化石墨烯复合材料（FeO/rGO），其中粒径约为 300nm 的 FeO 单晶均匀锚定在 rGO 纳米片上，为电子传输提供了高度导电的框架，并为材料在循环过程中的体积变化提供了灵活的基体。这种 FeO/rGO 复合阳极在 50mA/g 的电流密度下具有非常高的可逆容量 610mAh/g，在第一个循环中具有 71%的高库仑效率，在 100 次循环后具有 82%的容量保持率，表明其在钠离子电池中具有潜在的可行性。更重要的是，本工作清楚地表明，通过适当调整晶格结构、颗粒尺寸和电子传导通道，可以使简单的过渡金属氧化物具有高容量利用率、强倍率性能和稳定的循环稳定性，从而为开发低成本、高性能的钠离子存储电极提供了丰富的选择。
