Suppressing Lithium Polysulfide Shuttle in Li-S Batteries Using the AlPC₁₂ Composite for Enhanced Stability and Performance

This study presents the aluminum phosphate composite (AlPC₁₂) composite as a novel cathode material for lithium-sulfur (Li-S) batteries, addressing the polysulfide shuttle effect, a key challenge in Li-S battery performance. Synthesized via hydrolytic condensation and low-temperature calcination, the composite integrates aluminum alkoxide with phosphate to form a 3D structure that immobilizes lithium polysulfides (LiPS), enhancing battery efficiency and lifespan. Experimental analyses, including visible LiPS adsorption tests, and electrochemical measurements, demonstrate the superior performance of AlPC₁₂ over traditional cathodes. Electrochemical tests show that AlPC₁₂/S batteries exhibit exceptional discharge capacities and stability, outperforming titanium-based cathode and Super P cathode. At 0.5 C, the battery has an initial capacity of 837 mAh/g with a decay rate of 0.06% per cycle, and at 3 C, an initial capacity of 529 mAh/g with a decay rate of 0.08% per cycle. Increased sulfur loading does not affect LiPS control, with a 2.1 mg sulfur-loaded battery showing a decay rate of 0.03% over 750 cycles. Density functional theory (DFT) calculations confirm strong LiPS interactions, essential for efficient LiPS capture. This research promotes sustainability through a scalable, eco-friendly production process, minimizing environmental impact and advancing high-energy-density battery technologies.