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Nano-size porous carbon spheres as a high-capacity anode with high initial coulombic efficiency for potassium-ion batteries.
Nanoscale Horizons ( IF 8.0 ) Pub Date : 2020-03-10 , DOI: 10.1039/d0nh00018c
Hehe Zhang 1 , Chong Luo , Hanna He , Hong-Hui Wu , Li Zhang , Qiaobao Zhang , Haiyan Wang , Ming-Sheng Wang
Affiliation  

Hard carbon materials have been recognized as a promising family of anode materials for potassium ion batteries (PIBs), but their practical application is severely hindered due to the inferior initial coulombic efficiency (ICE) and low capacity. Herein, we report our findings in simultaneously improved potassium storage capacity and ICE through the design of nano-size and porous structure and the appropriate selection of electrolytes. Benefiting from the high specific surface area, stable electrode|electrolyte interface, and fast potassium ion and electron transfer, the optimized electrode exhibits a high ICE of up to 68.2% and an outstanding reversible capacity of 232.6 mA h g-1 at 200 mA g-1. In particular, superior cycling stability of 165.2 mA h g-1 at 1000 mA g-1 and 129.7 mA h g-1 at 2000 mA g-1 can be retained after 1500 cycles, respectively. Quantitative analysis reveals that this optimized structure leads to an enhanced surface-controlled contribution, resulting in fast potassiation kinetics and electronic|ionic conductivities, which are regarded as essential features for potassium storage. Our findings in this work provide an efficient strategy to significantly improve potassium storage capacity while maintaining a high ICE for hard carbon electrodes.

中文翻译:

纳米级多孔碳球作为高容量阳极,具有高的初始库仑效率,适用于钾离子电池。

硬碳材料已被公认为是钾离子电池(PIB)阳极材料的有希望的家族,但是由于初始库仑效率(ICE)较低和容量较低,严重阻碍了其实际应用。在此,我们通过纳米尺寸和多孔结构和电解质的适当选择的设计报告我们在同时改进钾存储容量和ICE发现。得益于高比表面积,稳定的电解质界面以及快速的钾离子和电子转移,优化后的电极在200 mA g时表现出高达68.2%的高ICE和232.6 mA h g-1的出色可逆容量。 -1。特别是,在1500次循环后,可以保持1000mA g-1时165.2 mA h g-1和2000mA g-1时129.7 mA h g-1的出色循环稳定性,分别。定量分析表明,这种优化的结构导致增强的表面控制作用,从而导致快速钾化动力学和电子电导率,这被认为是钾储存的基本特征。我们在这项工作中的发现提供了一种有效的策略,可以显着提高钾存储能力,同时保持硬碳电极的高ICE。
更新日期:2020-03-10
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