Influence of Polypyrrole on Phosphorus- and TiO₂-Based Anode Nanomaterials for Li-Ion Batteries

Phosphorus (P) and TiO₂ have been extensively studied as anode materials for lithium-ion batteries (LIBs) due to their high specific capacities. However, P is limited by low electrical conductivity and significant volume changes during charge and discharge cycles, while TiO₂ is hindered by low electrical conductivity and slow Li-ion diffusion. To address these issues, we synthesized organic-inorganic hybrid anode materials of P-polypyrrole (PPy) and TiO₂-PPy, through in situ polymerization of pyrrole monomer in the presence of the nanoscale inorganic materials. These hybrid anode materials showed higher cycling stability and capacity compared to pure P and TiO₂. The enhancements are attributed to the electrical conductivity and flexibility of PPy polymers, which improve the conductivity of the anode materials and effectively buffer volume changes to sustain structural integrity during the charge and discharge processes. Additionally, PPy can undergo polymerization to form multi-component composites for anode materials. In this study, we successfully synthesized a ternary composite anode material, P-TiO₂-PPy, achieving a capacity of up to 1763 mAh/g over 1000 cycles.