In Situ Electrophoretic Decorated Cactus-Type Metallic-Phase MoS₂ on CaMn₂O₄ Nanofibers for Binder-Free Next-Generation LIBs

Abstract

Ternary manganese-based oxides, such as CaMn 2 O 4 (CMO) nanofibers fabricated via the electrospinning technique, have the potential to offer higher reversible capacity through conversion reactions in comparison to that of carbon-based anodes. However, its poor electrical conductivity hinders its usage in lithium-ion batteries (LIBs). Hence, to mitigate this issue, controlled single-step in situ decoration of highly conducting metallic-phase MoS 2 @CMO nanofibers has been achieved for the first time via the electrophoretic deposition (EPD) technique and utilized as a binder-free nanocomposite anode for LIBs. Further, the composition of MoS 2 @CMO nanofibers has also been optimized to attain better electronic and ionic conductivity. The morphological investigation revealed that the flakes of MoS 2 nanoflowers are successfully and uniformly decorated over the CMO nanofibers' surface, forming a cactus-type morphology. As a binder-free nanocomposite LIB anode, CMOMS-7 (7 wt % MoS 2 @ CMO) demonstrates a specific capacity of 674 mA h g −1 after 60 cycles at 50 mA g −1 and maintains a capacity of 454 mA h g −1 even after 300 cycles at 1000 mA g −1 . Further, the good rate performance (102 mA h g −1 at 5000 mA g −1 ) of CMOMS-7 can be ascribed to the enhanced electrical conductivity provided by the metallic-phase MoS 2 . Moreover, the feasibility of CMOMS-7 is thoroughly investigated by using a full Li-ion cell incorporating a binder-free cathode of LiNi 0.3 Mn 0.3 Co 0.3 O 2 (NMC). This configuration showcases an impressive energy density of 154 Wh kg −1 . Thus, the hierarchical and aligned structure of CMO nanofibers combined with highly conductive MoS 2 nanoflowers facilitates charge transportation within the composite electrodes. This synergistic effect significantly enhances the energy density of the conversion-based nanocomposites, making them highly promising anodes for advanced LIBs.