摘要
It is highly important to develop ultrastable electrode materials for Li-ion batteries(LIBs),especially in the low temperature.Herein,we report Fe^(3+)-stabilized Ti_(3)C_(2)T_(x) MXene(donated as T/F-4:1)as the anode material,which exhibits an ultrastable low-temperature Li-ion storage property(135.2 m A h g^(-1)after300 cycles under the current density of 200 m A g^(-1)at-10℃),compared with the negligible capacity for the pure Ti_(3)C_(2)T_(x) MXene(26 m A h g^(-1)at 200 m A g^(-1)).We characterized as-made T/F samples via the Xray photoelectron spectroscopy(XPS),Fourier transformed infrared(FT-IR)and Raman spectroscopy,and found that the terminated functional groups(-O and-OH)in T/F are Li^(+) storage sites.Fe^(3+)-stabilization makes-O/-OH groups in MXene interlayers become active towards Li^(+),leading to much more active sites and thus an enhanced capacity and well cyclic stability.In contrast,only-O/-OH groups on the top and bottom surfaces of pure Ti_(3)C_(2)T_(x) MXene can be used to adsorb Li^(+),resulting in a low capacity.Transmission electron microscopy(TEM)and XPS data confirm that T/F-4:1 holds the highly stable solid electrolyte interphase(SEI)layer during the cycling at-10℃.Density functional theory(DFT)calculations further uncover that T/F has fast diffusion of Li^(+) and consequent better electrochemical performances than pure Ti_(3)C_(2)T_(x) MXene.It is believed that the new strategy used here will help to fabricate advanced MXene-based electrode materials in the energy storage application.
基金
supported financially by the Fundamental Research Funds for the Central Universities(Nos.2019RC021,2018JBZ107,2019RC035)
the National Natural Science Foundation of China(Nos.51971056,91961125,51802013,21905019)
the Key Program for International S&T Cooperation Projects of China from the Ministry of Science and Technology of China(No.2018YFE0124600)
the Chemistry and Chemical Engineering Guangdong Laboratory(Nos.1932004 and 1911021)
the financial support from Natural Science Foundation of Liaoning Province(No.20180510003)
support from the“Excellent One Hundred”Project of Beijing Jiaotong University。
