Modified reaction kinetics in ester-based electrolyte to boost sodium storage performance: a case study of MoS2/Ti3C2Tx hybrid

Abstract

Compared with ordinary ester-based electrolytes, the excellent match between ether-based electrolytes and transition-metal dichalcogenide (TMD) electrodes dramatically promotes their sodium storage performance. However, the origin of the superior electrochemical performance of TMD-based electrodes in ether-based electrolytes is still unclear. Herein, the MoS₂/Ti₃C₂T_x MXene (MoS₂/Ti₃C₂T_x) hybrid was taken as a typical example to reveal the fundamental principle of high Na⁺ storage performances with ether-based electrolytes. It has been demonstrated that the excellent long-term cyclability and reversibility of the MoS₂/Ti₃C₂T_x electrode can be mainly ascribed to the gradual structure evolution to form a stable porous structure with efficient buffering for strain upon cycling. Additionally, the high pseudocapacitive effect and ionic kinetics in ether-based electrolyte accelerate the charge transfer and reduce the electrochemical polarization. Significantly, X-ray photoelectron spectroscopy and interfacial kinetic studies demonstrate that the ether-based electrolyte enables a dense and thin SEI layer, which reduces the energy barrier for desolvation and shortens the transportation length of the charge carriers. Consequently, the MoS₂/Ti₃C₂T_x electrode exhibits excellent electrochemical performance in ether-based electrolyte, delivering a specific capacity of 288.2 mA h g⁻¹ after 3000 cycles at 3.0 A g⁻¹. Significantly, this work is essential for revealing the advantages of ether-based electrolytes for TMD-based electrodes in terms of rapid reaction kinetics, promoting their practical application in sodium-ion battery chemistry.