A material of hierarchical interlayer-expanded MoS2 nanosheets/hollow N-doped carbon nanofibers as a promising Li+/Mg2+ co-intercalation host

Abstract

Combining the high operational security of magnesium-ion batteries (MIBs) and the fast Li intercalation mechanism of lithium-ion batteries (LIBs), Li⁺/Mg²⁺ hybrid-ion batteries (LMIBs) have been developed and are regarded as a promising source of stored power for applications. However, pristine MoS₂ with an interplanar distance of 0.62 nm only allows Li⁺ intercalation, leading to limited energy densities and mediocre electrochemical performance. Herein, we designed and prepared a material consisting of hierarchical interlayer-expanded MoS₂ nanosheets/hollow N-doped carbon nanofibers (O–MoS₂/HN-CNFs) with interplanar expanded O–MoS₂ (0.94 nm). HN-CNFs adequately conduct electrons, and the expanded interlayer spacing of O–MoS₂ ensures that Mg²⁺ and Li⁺ simultaneously intercalate into the host, even at 1000 mA g⁻¹. Additionally, O–MoS₂/HN-CNFs can significantly reduce the ion diffusion barrier and increase the number of intercalated active sites. As a result, O–MoS₂/HN-CNFs exhibited superior rate capabilities, good cycling performance, and long-term cycling stability, with a reversible capacity of 134.4 mA h g⁻¹ at 1000 mA g⁻¹ after 2000 cycles.