Interfacial Kinetics and Ionic Diffusivity of the Electrodeposited MoS2 Film.

Abstract

The transition-metal disulfide (MoS2) is a fantastic material used in diverse fields of applications. Ionic diffusivity and interfacial exchange current density are model parameters that play a crucial role for the optimization of device performances, which are not clearly known for this material. The additive-free dense film of MoS2 has been deposited by a facile electrodeposition approach and characterized by structural, morphological, and compositional analyses. This report provides the characterization of interfacial charge-transfer kinetics and diffusion of lithium ion in the MoS2 films as a function of lithium concentration at 25 °C temperature. The interfacial exchange current density is observed to be varied barely, ∼0.069-0.066 mA/cm2, with the change of lithium content, from x = 0.01-0.25, in Li xMoS2. The ionic diffusivity of the film is found to be in the range of ∼3 × 10-11-10-11 cm2 s-1 and does not vary much with the measured lithium concentration window. The electrochemical performances of the material are limited by the transport of lithium ion and interfacial kinetics over the measured state of lithium content. A submicron-size particle with high surface area is needed to be used as an electrode of the material for practical C-rates.