Department of Chemical and Biomolecular Engineering, University of California , Los Angeles, California 90095, United States.
Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Department of Chemistry, Shanghai Normal University , Shanghai, 200234, China.
ACS Nano. 2017 Mar 28;11(3):2952-2960. doi: 10.1021/acsnano.6b08332. Epub 2017 Mar 15.
Sodium-ion capacitors can potentially combine the virtues of high power capability of conventional electrochemical capacitors and high energy density of batteries. However, the lack of high-performance electrode materials has been the major challenge of sodium-based energy storage devices. In this work, we report a microwave-assisted synthesis of single-crystal-like anatase TiO mesocages anchored on graphene as a sodium storage material. The architecture of the nanocomposite results in pseudocapacitive charge storage behavior with fast kinetics, high reversibility, and negligible degradation to the micro/nanostructure. The nanocomposite delivers a high capacity of 268 mAh g at 0.2 C, which remains 126 mAh g at 10 C for over 18 000 cycles. Coupling with a carbon-based cathode, a full cell of sodium-ion capacitor successfully demonstrates a high energy density of 64.2 Wh kg at 56.3 W kg and 25.8 Wh kg at 1357 W kg, as well as an ultralong lifespan of 10 000 cycles with over 90% of capacity retention.
钠离子电容器有望结合传统电化学电容器的高功率能力和电池的高能量密度。然而，缺乏高性能电极材料一直是基于钠的储能设备的主要挑战。在这项工作中，我们报告了一种微波辅助合成的单晶-like 锐钛矿 TiO 介孔笼锚定在石墨烯上作为储钠材料。该纳米复合材料的结构导致具有赝电容电荷存储行为的快速动力学、高可逆性和微/纳米结构的可忽略的降解。该纳米复合材料在 0.2 C 时提供了 268 mAh g 的高容量，在 10 C 时经过 18000 次循环后仍保持 126 mAh g。与碳基阴极耦合，钠离子电容器的全电池成功地展示了 64.2 Wh kg 的高能量密度，在 56.3 W kg 时为 25.8 Wh kg，在 1357 W kg 时为 10000 次循环的超长寿命，容量保持率超过 90%。
