Ultrathin graphdiyne oxide-intercalated MXene: A new heterostructure with interfacial synergistic effect for high performance lithium-ion storage

Two-dimensional (2D) layered heterostructures demonstrate strong interfacial synergistic effect, promote ion transfer and accelerate electrochemical reaction kinetics, and have great development potential in the field of energy storage. Here, ultra-thin 2D graphdiyne oxide (GDYO) was successfully prepared and creatively used as an intercalator to form a sandwich-like heterostructure with MXene (Ti3C2Tx) through electrostatic self-assembly. Intercalation of GDYO effectively extends the interlayer spacing of Ti3C2Tx nanosheets and meanwhile generates atomic interfacial electric fields within the heterostructure, leading to desirable pseudocapacitive behaviors and superior lithium-ion migration kinetics. Theoretical and experimental data reveal that the electrochemical performance of the heterostructure is superior to that of pure Ti3C2Tx or GDYO nanosheets when utilized as anodes for lithium-ion storage. A reversible capacity of ≈490.0 mAh g−1 at 2.0 A g−1 is attained by the Ti3C2Tx/GDYO-5 wt% heterostructure (≈770.0 mAh g−1 at 0.1 A g−1) with a long cycle life of 489.2 mAh g−1 after 1000 cycles.