Ultrafine Fe2VO4 nanoparticles anchored on Ti3C2Tx nanosheets (Fe2VO4@Ti3C2Tx) as high-energy anode for lithium-ion storage

Recently, as a new breakthrough for lithium-ion storage anode materials, transition metal vanadates, such as Fe2VO4, have attracted much attention, which, however, still suffer from slow electrochemical kinetics and substantial volume expansion. Hybrid with high conductivity materials is an effective route to deal with these issues. Herein, in situ synthesis of Fe2VO4@Ti3C2Tx composites with porous sandwich structure by co-precipitation-calcination process was reported. Ultrafine Fe2VO4 nanoparticles (10-15 nm) in situ grew and was anchored on Ti3C2Tx nanosheets, which effectively inhibits both the grain growth for Fe2VO4 and stacking for Ti3C2Tx, thus facilitating the electrochemical kinetics and alleviating the volume change of Fe2VO4 to maintain the integrated structure during the cycling process. As a result, Fe2VO4@Ti3C2Tx anode shows high Li+ diffusion coefficient (2.72×10-11 cm2·s-1) and pseudocapacitive charge storage mechanism (capacitive charge storage contribution 70.85%-84.80% at 0.2-1.0 mV·s-1), which guarantee rapid charging and discharging capability. Consequently, outstanding rate performance (1012 to 595 mAh·g-1 at 0.2 to 3.0 A·g-1) and superior cycling capability (663 and 416 mAh·g-1 at 1.0 A·g-1 for 200 cycles and 2.0 A·g-1 for 500 cycles, with the average capacity attrition rate of 0.059% and 0.053%, respectively), were achieved, which render Fe2VO4@Ti3C2Tx composites important potential for lithium-ion storage.