Zhou Xuefeng, Chen Lanlan, Zhang Wenhua, Wang Jiawei, Liu Zhenjie, Zeng Sifan, Xu Rui, Wu Ying, Ye Shufen, Feng Yuezhan, Cheng Xiaolong, Peng Zhangquan, Li Xifei, Yu Yan
Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science and Engineering, Key Laboratory of Materials for Energy Conversion , Chinese Academy of Sciences (CAS), University of Science and Technology of China , Hefei , Anhui 230026 , China.
Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Materials for Energy Conversion and Synergetic Innovation Centre of Quantum Information and Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China.
Nano Lett. 2019 Aug 14;19(8):4965-4973. doi: 10.1021/acs.nanolett.9b01127. Epub 2019 Jul 18.
The biggest challenge of potassium-ion batteries (KIBs) application is to develop high-performance electrode materials to accommodate the potassium ions large size. Herein, by rational design, we carbonize three-dimensional (3D) ordered macroporous ZIF-8 to fabricate 3D interconnected nitrogen-doped hierarchical porous carbon (N-HPC) that shows excellent rate performance (94 mAh g at 10.0 A g), unprecedented cycle stability (157 mA g after 12000 cycles at 2.0 A g), and superior reversible capacity (292 mAh g at 0.1 A g). The 3D hierarchical porous structure diminishes the diffusion distance for both ions/electrons, while N-doping improves the reactivity and electronic conductivity via producing more defects. In addition, the bicontinuous structure possesses a large specific surface area, decreasing the current density, again improving the rate performance. Raman spectra analysis confirms the potassiation and depotassiation in the N-HPC are highly reversible processes. The galvanostatic intermittent titration measurement and first-principles calculations reveal that the interconnected macropores are more beneficial to the diffusion of the K. This 3D interpenetrating structure demonstrates a superiority for energy storage applications.
钾离子电池（KIBs）应用面临的最大挑战是开发高性能电极材料以适应钾离子的大尺寸。在此，通过合理设计，我们将三维（3D）有序大孔ZIF-8碳化，制备出三维互连的氮掺杂分级多孔碳（N-HPC），其表现出优异的倍率性能（在10.0 A g下为94 mAh g）、前所未有的循环稳定性（在2.0 A g下循环12000次后为157 mA g）和出色的可逆容量（在0.1 A g下为292 mAh g）。三维分级多孔结构减小了离子/电子的扩散距离，而氮掺杂通过产生更多缺陷提高了反应活性和电子导电性。此外，双连续结构具有大的比表面积，降低了电流密度，再次提高了倍率性能。拉曼光谱分析证实N-HPC中的钾化和去钾化是高度可逆的过程。恒电流间歇滴定测量和第一性原理计算表明，互连的大孔对钾的扩散更有利。这种三维互穿结构在储能应用中显示出优势。
