PPy-Coated MoS/CoMoS Nanotube-like Heterostructure for High-Performance Lithium Storage.

Heterostructured materials show great potential to enhance the specific capacity, rate performance and cycling lifespan of lithium-ion batteries owing to their unique interfaces, robust architectures, and synergistic effects. Herein, a polypyrrole (PPy)-coated nanotube-like MoS/CoMoS heterostructure is prepared by the hydrothermal and subsequent in situ polymerization methods. The well-designed nanotube-like structure is beneficial to relieve the serious volume changes and facilitate the infiltration of electrolytes during the charge/discharge process. The MoS/CoMoS heterostructure could effectively enhance the electrical conductivity and Li transport kinetics owing to the refined energy band structure and the internal electric field at the heterostructure interface. Moreover, the conductive PPy-coated layer could inhibit the obvious volume expansion like a firm armor and further avoid the pulverization of the active material and aggregation of generated products. Benefiting from the synergistic effects of the well-designed heterostructure and PPy-coated nanotube-like architecture, the prepared MoS/CoMoS heterostructure delivers high reversible capacity (1251.3 mAh g at 300 mA g), superior rate performance (340.3 mAh g at 5.0 A g) and excellent cycling lifespan (744.1 mAh g after 600 cycles at a current density of 2.0 A g). Such a design concept provides a promising strategy towards heterostructure materials to enhance their lithium storage performances and boost their practical applications.