摘要
K-ion batteries(KIBs)hold great promise for large-scale energy storage.However,the absence of suitable cathode materials limits their practical application.Meanwhile,rationally designing advanced cathode materials for KIBs remains an open question.In this work,based on density functional theory calculations,we find that the bond stability of Fe–O is higher than that of Co–O in layered transitional metal(TM)oxides.Additionally,the K-ion migration in the Fe-based layered TM oxide has a significantly lower activation energy barrier than that in the Co-based one.Based on this theoretical prediction,we successfully synthesized a low-cost K_(0.45)Ni_(0.1)Fe_(0.1)Mn_(0.8)O_(2)cathode,which shows excellent structural stability and superior K-storage properties,including durable cycle life and high-rate capability.Moreover,the designed K_(0.45)Ni_(0.1)Fe_(0.1)Mn_(0.8)O_(2)cathode possesses a great full-cell performance with a discharge capacity of~75 mA h g^(-1) and capacity retention of~80%after 100 cycles.The results show that Fe has better structural stability and K-ion diffusion than high-cost Co in layered oxide cathodes,and this finding provides new insights into the design of low-cost and high-performance KIB layered cathodes.This work highlights the feasibility of a theory-guided experiment in screening promising battery materials.
钾离子电池在大规模储能方面具有广阔的前景.然而,缺乏合适的正极材料限制了其实际应用.此外,为钾离子电池合理设计先进的正极材料仍然面临挑战.本工作中,通过密度泛函理论计算,我们发现层状过渡金属氧化物中Fe-O键稳定性高于Co-O键.此外,Fe基层状氧化物中的钾离子迁移具有明显低于Co基氧化物的活化能垒.基于这一理论预测,我们成功合成了一种低成本的K_(0.45)Ni_(0.1)Fe_(0.1)Mn_(0.8)O_(2)正极,该正极显示出优异的结构稳定性和储钾性能,包括较长的循环寿命和高倍率性能.此外,所设计的K_(0.45)Ni_(0.1)Fe_(0.1)Mn_(0.8)O_(2)正极具有良好的全电池性能,放电容量约为75 mA h g^(-1),100次循环后容量保持率约为80%.在层状氧化物正极中,Fe比高成本Co具有更好的结构稳定性和钾离子扩散能力,这一发现为低成本和高性能钾离子电池层状正极的设计提供了新的思路.这项工作突出了以理论为指导的实验在筛选有前景的电池材料方面的可行性.
作者
Rongbin Dang
Qing-Bo Yan
Enyue Zhao
Na Li
Kang Wu
Zhongjun Chen
Zhonghua Wu
Xiangfeng Liu
Zhongbo Hu
Xiaoling Xiao
党荣彬;闫清波;赵恩岳;李娜;吴康;陈中军;吴忠华;刘向峰;胡中波;肖小玲(College of Materials Science and Optoelectronic Technology,Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;Songshan Lake Materials Laboratory,Dongguan 523808,China;Beijing Synchrotron Radiation Facility,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China)
基金
supported by the Fundamental Research Funds for the Central Universities and the Scientific Instrument Developing Project of the Chinese Academy of Sciences(ZDKYYQ20170001)。
