Dopamine Surface Functionalized 1D Titania Lepidocrocite Porous Mesostructured Particles for Improved Polysulfide Anchoring in Lithium Sulfur Cells

Lithium‐sulfur (Li‐S) batteries offer high specific capacities but their development is hindered by several issues, most notably polysulfide shuttle. Previously, a new form of titania nanomaterial, 1D lepidocrocite (1DL) nanofilaments was shown to serve as a sulfur (S) host for Li‐S batteries. In this work, porous mesostructured particles are introduced as a new morphology of the titania 1DL to improve its performance as a S host. Furthermore, employing a facile, aqueous, one‐step surface functionalization with dopamine enhances 1DL interactions with S, as confirmed by changes in infrared spectroscopy peaks and an increase in d‐spacing via X‐ray diffraction. This surface functionalization results in a reduction of 1DL band gap energy ( E g ) from 3.62 to ≈2.29 eV, resulting in a 2.6‐fold increase in electrical conductivity. Additionally, the surface functionalization renders a more conformal coating of S on the 1DL, leading to increased S utilization and interaction with the 1DL. Electrochemical testing shows a 20% reduction in the polysulfide shuttle current in comparison to base 1DL and 560 mAh g −1 at 0.5 C at a S‐loading of 2 mg cm −2 . Postmortem X‐ray photoelectron spectroscopy analysis also reveals stronger thiosulfate signals in the dopamine‐functionalized 1DLs, further confirming improved S interactions compared to untreated 1DL.