Confined MoS2 growth in a unique composite matrix for ultra-stable and high-rate lithium/sodium-ion anodes

Abstract

Although the achievements made for improving the stability of MoS2, active sites-loss resulting from layers stack and structure-collapse still exists in harsh conditions (e.g., super-high current density, low temperature). This is mainly because the current matrixes are lack of chemical anchoring effect and confinement ability for MoS2 growth. Herein, a new concept of “confined-growth MoS2” (noted as c-MoS2) is proposed to successfully prepare MoS2 with long life cycle performance especially in harsh conditions for lithium/sodium-ion batteries (LIBs/SIBs). A unique composite matrix consisted of carbon and carbonnitride TiO2 nanocrystals (TiO2 NCs) is designed to provide an ideal environment for MoS2 growth. The profound investigation on the formation process confirms an “in-situ driving nucleation and growth” mechanism, forming the designed covalent bond and confinement effect between matrix and MoS2. As a result, the capacity of c-MoS2 at 5 A g−1 maintains 450 mAh g−1 for 600 cycles with no fading in LIBs, and reaches more than 220 mAh g−1 for 2000 cycles at 1 A g−1 in SIBs. Especially, super-stable performance at low temperature (0 °C and −25 °C), and rechargeable lithium-ion full battery coupled with LiNiCoMnO2 cathode are achieved. This unique composite matrix and novel concept provide an insight into designing stable two-dimension materials as well as their application in fast charging batteries.