Design of Vertically Aligned Two-Dimensional Heterostructures of Rigid Ti 3 C 2 T X MXene and Pliable Vanadium Pentoxide for Efficient Lithium Ion Storage.

Designing a thick electrode with appropriate mass loading is a prerequisite toward practical applications for lithium ion batteries (LIBs) yet suffers severe limitations of slow electron/ion transport, unavoidable volume expansion, and the involvement of inactive additives, which lead to compromised output capacity, poor rate perforamnce, and cycling instability. Herein, self-supported thick electrode composed of vertically aligned two-dimensional (2D) heterostructures (V-MXene/V ₂ O ₅ ) of rigid Ti ₃ C ₂ T _X MXene and pliable vanadium pentoxide are assembled via an ice crystallization-induced strategy. The vertical channels prompt fast electron/ion transport within the entire electrode; in the meantime, the 3D MXene scaffold provides mechanical robustness during lithiation/delithiation. The optimized electrodes with 1 and 5 mg cm ^-2 of V-MXene/V ₂ O ₅ respectively deliver 472 and 300 mAh g ^-1 at a current density of 0.2 A g ^-1 , rate performance with 380 and 222 mAh g ^-1 retained at 5 A g ^-1 , and reliability over 800 charge/discharge cycles.