Soukupová G., Matějka F., Vlčková Živcová Z., Laachachi A., Galář P., Lhotka M., Frank O., Červenka J., Hassouna F.
Journal of Power Sources, vol. 661, art. no. 238620, 2026
Silicon (Si) is a promising anode material for Li-ion batteries (LIBs), but its practical application is limited by volume expansion during lithiation/delithiation, leading to poor cycling stability. While Si nanostructuring mitigates this issue, it remains only a partial solution.This study systematically investigates the effects of Si particle size (6, 20, 55, or 100 nm), surface chemistry (type and degree of oxidation), and solid-state properties (amorphous vs. crystalline) on the electrochemical performance of Si-based anodes using a three-dimensional (3D) crosslinked polypyrrole (PPy) binder. In situ PPy polymerization around Si nanoparticles forms a 3D interconnected conductive network within the PPy/Si anodes, effectively accommodating volume changes and maintaining electrical contact during the galvanostatic cycling. The particle size dependence shows that larger Si nanoparticles provide higher initial charge capacity (2975 mAh/g), whereas smaller ones improve cycling stability (85 % capacity retention after 100 cycles). Amorphous Si exhibits significantly lower specific capacity but superior capacity retention (∼100 % after 100 cycles) compared to crystalline Si. Cyclic voltammetry and electrochemical impedance spectroscopy demonstrate that integrating 6 or 20 nm Si nanocrystals into a 3D crosslinked PPy enhances anode performance. These findings highlight the importance of optimizing Si properties in designing conductive hydrogel-derived anodes for high-performance LIBs.
