Ethanol Molecule Engineering Toward Stabilized 1T-MoS2 with Extraordinary Sodium Storage Performance.

Phase molybdenum disulfide (1T-MoS2) holds significant promise as an anode material for sodium-ion batteries (SIBs) due to its metallic conductivity and expanded interlayer distance. However, the practical application of 1T-MoS2 is hindered by its inherent thermodynamic metastability, which poses substantial challenges for the synthesis of high-purity, long-term stable 1T phase MoS2. Herein, a synergetic ethanol molecule intercalation and electron injection engineering is adopted to induce the formation and stabilization of 1T-MoS2 (E-1T MoS2). The obtained E-1T MoS2 consists of regularly arranged sphere-like ultrasmall few-layered 1T-MoS2 nanosheets with expanded interlayer spacing. The high intrinsic conductivity and enlarged interlayer spacing are greatly favorable for rapid Na+ or e- transport. The elaborated nanosheets structure can effectively relieve volume variation during Na+ intercalating/deintercalating processes, shorten transport path of Na+, and enhance diffusion kinetics. Furthermore, a novel sodium reaction mechanism involving the formation of MoS2 nanoclusters during cycling is revealed to produce the higher surface pseudocapacitive contribution to Na+ storage capacity, accelerating Na+ reaction kinetics, as confirmed by the kinetics analysis and ex-situ structural characterizations. Consequently, the E-1T MoS2 electrode exhibits an excellent sodium storage performance. This work provides an important reference for synthesis and reaction mechanism analysis of metastable metal sulfides for advanced SIBs.