On the implications of silver addition for the structure and anodic performance of polyaniline/(FeCoNiCrMn)3O4 high-entropy oxide composite used in lithium-ion batteries

This study focuses on enhancing the performance of (FeCoNiCrMn)3O4 high-entropy oxide (HEO) anodes for lithium-ion batteries (LIBs) by adding polyaniline (PANI) and silver (Ag). The HEO was synthesized using a solid-state method, involving ball milling and high-temperature heat treatment, which resulted in a stable spinel structure. To further improve its properties, the HEO powder was coated with a PANI-Ag layer via oxidative polymerization and the addition of silver nanoparticles, enhancing conductivity and mitigating lithium dendrite formation. The HEO-P-Ag composite demonstrated significant improvements compared to the unmodified HEO. The initial discharge capacity of HEO-P-Ag was 1050.8 mA hg−1, while its charge capacity was 711 mA h g−1, both of which exceeded the corresponding values of the bare HEO (827 mA h g−1 for discharge and 445 mA h g−1 for charge). Additionally, the composite also exhibited good rate capability, achieving a reversible capacity of 265 mA h g−1 at a rate of 1C. Electrochemical impedance spectroscopy (EIS) confirmed that the PANI-Ag coating effectively reduced charge transfer resistance and enhanced lithium ion diffusion. Accordingly, these findings indicate that HEO-P-Ag could serve as a promising anode material for high-performance LIBs, delivering high capacity, improved rate capability, and stable cycling performance.