Multi-ion competition mechanism within MXene interlayer and Li ion intercalated electrode function

Abstract

2D layered MXene material offers atomic level intervals that can expand the function of ion intercalated electrode. Challenges remain in modulating the interlayer environment and overcome the problem of lamellar stacking. Herein, to accurate control the interlayer structure of MXene and understand these ions confined by MXene, Li+, Na+ and K+ are pre-inserted into the inner space, which is the spaced voids of two adjacent Ti3C2Tx MXene layers with Al3+ ions, and the relationship between the interlayer spacing and the multi-ion interaction mechanism is explored. Furthermore, the electrochemical behavior and performance induced by multi-ion intercalated MXene electrodes are evaluated. The results show that the capacity of MXene electrodes with Na+ pre-intercalation obtained a capacity of 250.80 mAh g−1, and the capacity is maintained after 200 cycles is 179.67 mAh g−1, which attenuation is 28.36%. In addition, the pre-intercalated Na+ ions can maintain a more stable structure and benefit to electrochemical cycling performance than these pre-intercalated Li+ ions occupying the transport channels of the electrolyte ion. It provides data support for in-depth understanding of the mechanism and derivation of ion pre-intercalated MXene.