Double-phase 1T/2H–MoS2 heterostructure loaded in N-doped carbon/CNT complex carbon for efficient and rapid lithium storage

Abstract

MoS2 has been considered as a potential anode for lithium-ion batteries. Most of the lab-prepared MoS2 anode materials are 2H phase with low intrinsic conductivity. To compensate the intrinsic low conductivity of 2H–MoS2 and its structural instability in cycles, a N-doped carbon-carbon nanotube (NC-CNT) carbon complex is prepared as the basic structure for MoS2 growth, and a 1T/2H–MoS2 heterostructure is fabricated on this structure. On one hand, CNTs create additional pores and connect isolated sheets of the NC, which provides enough inner growth space for MoS2 and maintains the overall electrical conductivity. On the other hand, the double-phase 1T/2H–MoS2 with high content (60%) of the metallic 1T-MoS2 gives a larger layer spacing, higher internal electron conductivity, and more active lithiation and de-lithiation reactions. To serve as anode for lithium-ion batteries, the synthesized 1T/2H–MoS2@NC–CNT has a reversible capacity of 764.99 mAh g−1 at 200 mA g−1 and an high-rate capacity of 547.7 mAh g−1 at 1000 mA g−1 even after 1000 cycles. By studying the reaction kinetics, impedance and lithiation/delithiation mechanism during electrochemical reactions, it is concluded that 1T/2H–MoS2@NC–CNT obtains declined charge transfer resistance, accelerated diffusion of Li+, improved cyclic stability, and enhanced structure/property reversibility from the carbon complex and the high-content 1T phase MoS2.