| Abstract: | It is highly important to develop ultrastable electrode materials for Li-ion batteries (LIBs),especially in the low temperature.Herein,we report Fe3+-stabilized Ti3C2Tx MXene (donated as T/F-4∶1) as the anode material,which exhibits an ultrastable low-temperature Li-ion storage property (135.2 mA h g-1 after 300 cycles under the current density of 200 mA g-1 at-10 ℃),compared with the negligible capacity for the pure Ti3C2Tx MXene (～26 mA h g-1 at 200 mA 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.Fe3+-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 Ti3 C2Tx 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 Ti3C2Tx MXene.It is believed that the new strategy used here will help to fabricate advanced MXene-based electrode materials in the energy storage application. |
