Molten salt electrochemical synthesis of low-cost Vn+1AlCn (n=1,3) and their derived two-dimensional MXenes

摘要

? 2022 Elsevier Ltd and Techna Group S.r.l.Herein we report a molten salt electrochemical approach to synthesize two MAX phases, V2AlC and V4AlC3, using inexpensive V2O3, Al2O3, and graphite as raw materials. The oxides/carbon mixture is directly reduced into MAX phases under cathodic polarization at moderate temperatures (600–850 °C). The corresponding MXenes, V2CTx and V4C3Tx, are successfully produced through the HF etching method. The optimized molar ratio of V2O3/Al2O3/C precursor for V2AlC synthesis is achieved, and the resulting V2CTx film possesses great stability in air at 30 °C for at least 10 days. Furthermore, the obtained V2CTx and V4C3Tx exhibit excellent capacities of 468 mAh g?1 and 152 mAh g?1 after 100 cycles, respectively, at a current density of 100 mA/g, comparable to those made from conventional methods.