Hierarchical Hollow‐Nanocube Ni−Co Skeleton@MoO₃/MoS₂ Hybrids for Improved‐Performance Lithium‐Ion Batteries

Abstract

Improving the performance of anode materials for lithium-ion batteries (LIBs) is a hotly debated topic. Herein, hollow Ni-Co skeleton@MoS₂ /MoO₃ nanocubes (NCM-NCs), with an average size of about 193 nm, have been synthesized through a facile hydrothermal reaction. Specifically, MoO₃ /MoS₂ composites are grown on Ni-Co skeletons derived from nickel-cobalt Prussian blue analogue nanocubes (Ni-Co PBAs). The Ni-Co PBAs were synthesized through a precipitation method and utilized as self-templates that provided a larger specific surface area for the adhesion of MoO₃ /MoS₂ composites. According to Raman spectroscopy results, as-obtained defect-rich MoS₂ is confirmed to be a metallic 1T-phase MoS₂ . Furthermore, the average particle size of Ni-Co PBAs (≈43 nm) is only about one-tenth of the previously reported particle size (≈400 nm). If assessed as anodes of LIBs, the hollow NCM-NC hybrids deliver an excellent rate performance and superior cycling performance (with an initial discharge capacity of 1526.3 mAh g^-1 and up to 1720.6 mAh g^-1 after 317 cycles under a current density of 0.2 A g^-1 ). Meanwhile, ultralong cycling life is retained, even at high current densities (776.6 mAh g^-1 at 2 A g^-1 after 700 cycles and 584.8 mAh g^-1 at 5 A g^-1 after 800 cycles). Moreover, at a rate of 1 A g^-1 , the average specific capacity is maintained at 661 mAh g^-1 . Thus, the hierarchical hollow NCM-NC hybrids with excellent electrochemical performance are a promising anode material for LIBs.