Abstract
Lithium-sulfur (Li-S) batteries are promising next-generation energy storage systems, but their practical deployment remains hindered by polysulfide shuttling, sluggish sulfur redox kinetics, and structural instability during cycling. Herein, a freestanding carbon fiber paper (CFP) electrode decorated with spherical TiO 2 and Ni nanoparticles (NPs) is developed as a multifunctional sulfur host that integrates polysulfide confinement, catalytic conversion, and continuous charge transport. Systematic comparison of CFP, TiO 2 @CFP, TiO 2 /NiO@CFP, and TiO 2 /Ni@CFP distinguishes the respective roles of the conductive scaffold, adsorption-active oxide domains, and metallic catalytic sites. Benefiting from the synergistic combination of TiO 2 -mediated polysulfide adsorption and Ni-assisted redox conversion, the TiO 2 /Ni@CFP cathode delivers an initial specific capacity of 1484.5 mAh g -1 at 0.2 C with a sulfur loading of 2 mg cm -2 and retains 76.3% of its capacity with a Coulombic efficiency (CE) of 95.7% after 100 cycles. It also maintains 478.2 mAh g -1 after 500 cycles and delivers 1427.9 mAh g -1 at 8 mg cm -2 . In situ Raman spectroscopy, electrochemical impedance spectroscopy, Li 2 S precipitation tests, and density functional theory calculations reveal a cooperative adsorption-catalysis mechanism, providing an effective oxide-metal coupling strategy for high-performance freestanding Li-S cathodes.