Li Hongyang, Sun Xiao, Gou Huiyang, Zhang Chengwei, Wang Gongkai
School of Materials Science & Engineering and Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology, Hebei University of Technology, Tianjin 300130, China.
Center for High Pressure Science and Technology Advanced Research, Beijing 100094, China.
J Colloid Interface Sci. 2023 May 15;638:161-172. doi: 10.1016/j.jcis.2023.01.085. Epub 2023 Jan 20.
TiO is considered as a low cost, long-term stable, and safe anode for high power K-ion hybrid capacitors (KICs) due to its abundant reserve, small volume expansion rate, and sloping voltage plateau that avoids K-ion plating at high voltage polarization. However, the enhancement of its low capacity and sluggish kinetics caused by poor electroconductivity and high insertion barrier is still challenging to further develop high-performance KICs. Herein, the reduced graphene oxide (rGO) is embedded in the walls of 3D ordered macro-/mesoporous TiO (termed as TiO@rGO framework) to create intimate TiO/rGO interfaces, ensuring the effectively electron transportation during potassiation/depotassiation of TiO while maintaining rapid ions/electrolyte diffusion. Furthermore, the controlled amorphous TiO framework can further lower the lattice insertion energies, contributing to a fast accommodation of K-ion. As expected, the amorphous TiO@rGO framework (TiO@rGO-1) exhibits a superior rate capability (148.8 mAh g at 5 A g) and cycling stability (171.2 mAh g at 1 A g after 800 cycles). The assembled KICs can reach a high energy/power density of 125.2 Wh kg/4267.4 W kg as well as a long-term lifespan. This tactic provides a reliable and general way to design a TiO-based anode with fast kinetics toward high-performance KICs.
由于钛储量丰富、体积膨胀率小以及具有倾斜的电压平台可避免在高电压极化时钾离子镀覆，TiO被认为是用于高功率钾离子混合电容器（KICs）的低成本、长期稳定且安全的阳极。然而，由于导电性差和插入势垒高导致其低容量和缓慢动力学的问题，对于进一步开发高性能KICs而言仍然具有挑战性。在此，将还原氧化石墨烯（rGO）嵌入三维有序大孔/介孔TiO的壁中（称为TiO@rGO框架）以创建紧密的TiO/rGO界面，确保在TiO的钾化/脱钾过程中有效地进行电子传输，同时保持快速的离子/电解质扩散。此外，可控的非晶TiO框架可以进一步降低晶格插入能，有助于快速容纳钾离子。正如预期的那样，非晶TiO@rGO框架（TiO@rGO-1）表现出优异的倍率性能（在5 A g时为148.8 mAh g）和循环稳定性（在1 A g下循环800次后为171.2 mAh g）。组装的KICs可以达到125.2 Wh kg/4267.4 W kg的高能量/功率密度以及长寿命。这种策略为设计具有快速动力学的基于TiO的阳极以实现高性能KICs提供了一种可靠且通用的方法。
