Non-desolvation Zn 2+ storage mechanism enables MoS 2 anode with enhanced interfacial charge-transfer kinetics for low temperature zinc-ion batteries

The emerging rocking-chair aqueous zinc-ion battery (AZIB) configuration provides a promising approach for realizing their practical applications by avoiding the critical drawbacks of Zn metal anodes including unsatisfactory Coulombic efficiency and low Zn utilization. Therefore, exploiting appropriate insertion-type anodes with fast charge-transfer kinetics is of great importance, and many modifications focusing on the improvement of electron transport and bulk Zn 2+ diffusion have been proposed. However, the interfacial Zn 2+ transfer determined by the desolvation process actually dominates the kinetics of overall battery reactions, which is mainly overlooked. Herein, the interlayer structure of MoS 2 is rationally co-intercalated with water and ethylene glycol (EG) molecules (MoS 2 @EG), giving rise to a fast non-desolvation Zn 2+ storage mechanism, which is verified by the extraordinarily smaller activation energy of interfacial Zn 2+ transfer (4.66 kJ mol −1 ) compared with that of pristine MoS 2 (56.78 kJ mol −1 ). Furthermore, the results of theoretical calculations, in-situ Raman and ex-situ characterizations also indicate the enhanced structural integrity of MoS 2 @EG during cycling due to the enlarged interlayer spacing and charge screening effect induced by interlaminar EG molecules. Consequently, the MoS 2 @EG anode enables excellent cycling stability of both high-energy-density MoS 2 @EG∥PVO (polyaniline intercalated V 2 O 5 ) and high-voltage MoS 2 @EG∥Na 3 V 2 (PO 4 ) 2 O 2 F (NVPF) full batteries with neglectable capacity decay at −20 °C.