Are Janus MoSSe/Ti3C2-MXene heterostructures excellent anode materials for Na-ion batteries? A computational insight combined experiment

The heterostructures composed of transition-metal dichalcogenides and MXene show excellent performance as Na-ion batteries anodes. Herein, the electrochemical performance of MoSe2/MXene is verified to be better than that of MoS2/MXene through experiments. Thereafter, first-principles calculations on electronic properties and electrochemical performances of MoSSe/MXene, MoSeS/MXene, MoSe2/MXene and MoS2/MXene are all performed to investigate Janus heterostructures’ feasibility as anodes. Diffusion barrier of MoSSe/MXene is slightly higher than that of MoSe2/MXene. Moreover, calculations of electronic properties reveal that the conductivity of the heterostructures is mainly provided by MXenes. Especially when the Se is connected with MXene, the conductivities of corresponding heterostructures are better as shown by MoSSe/MXene, followed by MoSe2/MXene. Then from crystal orbital Hamilton population, the strength of O-Na is proportional to that of S/Se-Na. Finally, MoSSe/Ti3C2-MXene possesses lower open circuit voltage (1.538 V) and higher theoretical capacity (593.3 mAh/g) than MoSe2/Ti3C2-MXene according to calculation results, which is more suitable for Na-ion batteries anodes. While overall performance tests show that MoSeS/MXene does not perform well. This work provides evidence to realize potential of Janus heterostructures as anodes for Na-ion batteries.