Construction of two-dimensional bimetal (Fe-Ti) oxide/carbon/MXene architecture from titanium carbide MXene for ultrahigh-rate lithium-ion storage.

Abstract The development of battery systems with high specific capacity and power density could fuel various energy-related applications from personal electronics to grid storage. (Fe2.5Ti0.5)1.04O4 possessing high theoretical specific capacity has been considered as a promising high rate anode material for lithium ion batteries due to the replacement of Fe3+ (0.64 A) by Ti4+ (0.68 A) with a larger radius to expand the interlayer space for ion intercalation. However, its extreme volume variation upon cycling as well as poor electrical conductivity hinder its further application. To tackle the above problems, in this work, we successfully synthesized two-dimensional (2D) (Fe2.5Ti0.5)1.04O4/C/MXene architecture derived from Ti3C2Tx MXene via solvo-hydrothermal, ultrasound hybridizing and high temperature annealing processes. The (Fe2.5Ti0.5)1.04O4/C/MXene shows a high discharge capacity of 757.2 mAh g−1 after 800 cycles at a current density of 3 A g−1 with excellent rate performance. The superior electrochemical performances are triggered primarily by the incorporation of carbon and MXene into (Fe2.5Ti0.5)1.04O4 moiety to construct a 2D layered structure, which can improve the ion diffusion and electron transport. In addition, the synergistic contributions from diffusion controlled and capacitive processes for (Fe2.5Ti0.5)1.04O4/C/MXene improve the ion diffusion rate and offer high specific capacity at high current density. The MXene-derived synthesis strategy in this work should be a promising pathway to synthesize other anode materials with 2D layered architecture for high performance lithium storage.