Two-dimensional V4C3 MXene as high performance electrode materials for supercapacitors

Two-dimensional (2D) MXenes such as Ti3C2, Ti2C, Mo2C, and Mo133C have shown excellent electrochemical performances as supercapacitor electrodes, and the exploration of new and/or high-capacity MXene-based supercapacitor electrode materials is an active field. In this work, 2D multi-layered V4C3 MXene has been synthesized by selectively etching Al from V4AlC3 and it shows a high capacitance of 209 F g(-1) at 2 mV s(-1), good rate performance, and stable long cyclic performance with capacitance retention rate of 97.23% after 10000 cycles at 10 A g(-1) in 1 M H2SO4. Importantly, the pseudocapacitance (similar to 100.1 F g(-1)) accounts for about 37% of the total capacity (similar to 268.5 F g(-1)) for V4C3 MXene electrode. Therefore, the high specific capacitance of V4C3 MXene is not only due to their wide interlayer spacing (similar to 0.466 nm), large specific surface areas (similar to 31.35 m(2) g(-1)) and pore volumes (similar to 0.047 cm(3) g(-1)), and good hydrophilicity but also attributed to the abundant valence states of vanadium (+2, +3, and +4). The high rate performance and excellent cycling stability of V4C3 MXene electrodes are mainly attributed to the high electronic conductivity (1137 S m(-1) at 300 K). The present work provides another promising MXene-based supercapacitor electrode material. (C) 2019 Elsevier Ltd. All rights reserved.