Structural, morphological, and electrochemical characterization of MoS2/fumed silica composite anodes for enhanced lithium-ion battery performance

Abstract

In this study, MoS2-fumed silica composites were synthesized via probe sonication and slurry casting. The incorporation of fumed silica at varying concentrations (10-30%) significantly influenced the electrochemical performance. The main finding is that the 20% fumed silica composite achieved the best balance of high specific capacity, enhanced cycling stability, and improved rate capability. Incorporating fumed silica (SiO2) into MoS2-based anodes significantly enhances their electrochemical performance for lithium-ion batteries. The 20% SiO2 composite emerged as the optimal formulation, delivering a remarkable discharge capacity of 980 mAh/g at 0.1C-nearly double that of pristine MoS2 (540 mAh/g). The composite also maintained better cycling stability and rate capability, with a capacity retention of approximately 90 mAh/g after 100 cycles at a 1C rate, compared to 65 mAh/g for pristine MoS2. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses demonstrated that the 20% fumed silica composite exhibited the most distinct redox peaks, reduced charge transfer resistance (Rct), and enhanced Li+ diffusion, indicating improved electrode architecture and ionic transport. The Nyquist plots revealed that the 20% composition had the smallest semicircle diameter, corresponding to the lowest Rct, further supporting its superior electrochemical behavior. This enhancement is attributed to the synergistic effects of MoS2's high capacity and fumed silica's porous structure, which mitigates volume expansion, improves electronic conductivity, and provides mechanical stability. The results demonstrate that the MoS2-20% fumed silica composite effectively balances high capacity, cycling stability, and rate performance, making it a promising candidate for next-generation LIB anodes. This work provides valuable insights into the design of hybrid materials for energy storage applications and highlights the potential of fumed silica as a matrix material to enhance the electrochemical properties of MoS2-based anodes.