Flexible electrode based on multi-scaled MXene (Ti₃C₂T_x) for supercapacitors

MXenes is one of the most promising flexible electrode materials for supercapacitor. However, the nanosheets in the MXenes electrode by vacuum filtration are prone to restack during preparation, which largely hinders the full utilization of their surfaces and active sites. In this contribution, the self-restacking of MXene nanosheets (prepared by etching with HCl + LiF) could be prevented effectively by introducing MXene nanoparticles (prepared by etching with HF) as interlayer spacers. The Ti₃C₂T_x-10 flexible (the electrode with 10% mass fraction nanoparticles) exhibits an excellent specific capacitance of 372 F g⁻¹ at 1 A g⁻¹ which is much higher than that of Ti₃C₂T_x film, and an impressive cycling stability up to 95% capacitance retention after 5000 cycles. The significant improvement in electrochemical performance is mainly due to that the open sandwich-like structure of the flexible electrode based on multi-scaled Ti₃C₂T_x provides huge surface area and more active sites.