Interface-engineered metallic 1T-MoS2 nanosheet array induced via palladium doping enabling catalysis enhancement for lithium-oxygen battery

Lacking strategy to enhance the intrinsic catalytic activity and site density of hexagonal molybdenum disulfide (2H-MoS2) is restricting their further development as viable electrocatalysts for lithium-oxygen (Li-O-2) battery. Here, palladium (Pd) induced metallic (1T) MoS2 nanosheet array supported on carbon textiles (Pd-TMS/CT) was deliberately fabricated as a high-efficient freestanding cathode of Li-O-2 battery. Transforming semi-conducting 2H phase to the stabilized metallic 1T phase of MoS2 was induced by doping Pd using a spontaneous interfacial redox strategy. This novel class of 1T-MoS2 nanosheet array with unique electronic structures enables the electrode with fast reaction kinetics, high electrical transport rate, and proliferated catalytic active sites, which lead to a striking improvement of their intrinsic catalytic behavior in Li-O-2 battery. In addition, the synergistic effect with well-designed surface chemistry of MoS2 is favorable for the reversible formation and decomposition of products and the inhibition of side reactions on Pd-TMS/CT cathode. As a result, the battery with Pd-TMS/CT exhibits outstanding electrochemical behavior in terms of high discharge capacity of 7441 mA h g(-1), low overpotential, and especially the excellent electrochemical stability for over 2488 h (622 cycles). Moreover, due to its flexibility superiority, the assembled pouch-type battery based on Pd-TMS/CT cathode can stably operate in real air atmosphere under different bending and twisting conditions, which opens up a variety of potential applications of flexible devices with high energy density.