Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA.
State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
Science. 2017 May 12;356(6338):599-604. doi: 10.1126/science.aam5852.
Nanostructured materials have shown extraordinary promise for electrochemical energy storage but are usually limited to electrodes with rather low mass loading (~1 milligram per square centimeter) because of the increasing ion diffusion limitations in thicker electrodes. We report the design of a three-dimensional (3D) holey-graphene/niobia (NbO) composite for ultrahigh-rate energy storage at practical levels of mass loading (>10 milligrams per square centimeter). The highly interconnected graphene network in the 3D architecture provides excellent electron transport properties, and its hierarchical porous structure facilitates rapid ion transport. By systematically tailoring the porosity in the holey graphene backbone, charge transport in the composite architecture is optimized to deliver high areal capacity and high-rate capability at high mass loading, which represents a critical step forward toward practical applications.
纳米结构材料在电化学储能方面表现出了非凡的应用前景，但由于在较厚的电极中离子扩散限制的增加，通常仅限于质量负载较低的电极（~1 毫克每平方厘米）。我们报告了一种三维（3D）多孔石墨烯/氧化铌（NbO）复合材料的设计，该复合材料可在实际质量负载水平（>10 毫克每平方厘米）下实现超高倍率储能。3D 结构中高度互联的石墨烯网络提供了优异的电子传输性能，其分级多孔结构有利于快速离子传输。通过系统地调整多孔石墨烯骨架中的孔隙率，优化了复合结构中的电荷传输，从而在高质量负载下实现了高面积容量和高倍率性能，这是朝着实际应用迈出的关键一步。
