Rational design of coral ball-like MoS2/N-doped carbon nanohybrids via atomic interface engineering for effective sodium/potassium storage

Abstract

MoS₂ with a graphite-like layered structure has been regarded as a promising electrode for sodium-ion batteries (SIBs)/potassium-ion batteries (PIBs) due to its high theoretical capacity. Unfortunately, the poor intrinsic electrical conductivity and limited interlayer distance of MoS₂ result in unsatisfactory electrochemical performance of SIBs and PIBs, which greatly restrict its further development. Herein, coral ball-like MoS₂/N–C nanohybrids have been designed and prepared purposely as electrode materials for SIBs and PIBs. The alternate intercalation of N-doped porous carbon (N–C) leads to ultrathin MoS₂ nanosheets with an expanded interlayer spacing of MoS₂ (0.98 nm), which can endow the facilitative ion diffusion and accommodate the tremendous volume variation. In addition, the MoS₂ chemically bonded with N–C could not only greatly enhance the electrical conductivity and facilitate the electron transport, but also maintain the structural stability of the electrode. As expected, when used as an electrode for SIBs, the MoS₂/N–C electrode achieves a remarkable long-term lifespan (222 mA h g⁻¹ at 5 A g⁻¹ after 1000 cycles). In addition, it also displays an enhanced cycling life (175 mA h g⁻¹ at 2 A g⁻¹ after 500 cycles) for PIBs.