Anode Material for Lithium-Ion Batteries Based on MoS2 and Conductive Polymer Binder: Effects of Electrode Thickness

High specific capacity of anode materials based on MoS2 is attractive for their use in lithium-ion batteries. However, low cycling stability of bulk MoS2 and complicated conversion mechanism of charge storage are major challenges for adoption of such materials as anodes for lithium-ion batteries. In this work, we focus on the effects of electrode thickness on electrochemical performance of anodes based on MoS2. We assess whether variation of thickness is a viable strategy to enhance the stability of such materials. Among electrodes with thickness varied within 70-250 μm, those with 100 μm to 150 μm material thickness display the most favorable rate capability in galvanostatic charge-discharge tests (32% of initial capacity at 2 A g), which is linked to their low charge transfer resistance, as shown by electrochemical impedance spectroscopy. We also show that conductive polymer binder based on PEDOT:PSS and CMC facilitates charge transfer, as compared to conventional PVDF binder. Electrochemical studies and investigations with SEM, HR-XRD, and XPS methods show that irreversible processes occur in the electrodes and point at the necessity of substantial MoS2 materials modification to preserve their stability.