Strengthened dipole-dipole interaction on high-entropy oxide electrocatalysts for high-rate and excellently stable lithium-sulfur batteries

The diverse functional polar active sites in high-entropy oxides enhance the dipole-dipole interaction with polar polysulfides , thus inhibiting polysulfide shuttling and accelerating redox reaction kinetics. Electrocatalysts are an effective strategy to mitigate the shuttling effect of lithium polysulfides (LiPSs) and accelerate the redox kinetics of LiPSs in lithium-sulfur (Li-S) batteries. However, traditional electrocatalysts only have a single active site and often undergo structural collapse and aggregation during charging and discharging, resulting in reduced catalytic performance. Herein, the two-dimensional (2D) polar high-entropy La 0.71 Sr 0.29 Co 0.21 Ni 0.20 Fe 0.19 Cr 0.20 Cu 0.20 O 3 (LCO-HEO) nanosheets were rationally designed and successfully synthesized to address this issue. The distinct functional polar sites in LCO-HEOs were formed by the d - d orbital hybridization between spatially coupling adjacent transition metals, which can strengthen the dipole-dipole interaction between polar LCO-HEOs and polar LiPSs. 2D polar LCO-HEO nanosheets can efficiently capture and trigger the tandem catalysis of polar LiPSs during their sequential conversion. The S/LCO-HEO composite cathode exhibits a high specific capacity of 1161.1 mA h g −1 at 1.0 C, with an ultralow capacity attenuation rate of 0.036% per cycle over 1200 cycles, and achieves stable cycling for 1500 cycles even at 8.0 C. Furthermore, even with a high sulfur loading (5.5 mg cm −2 ) and a low electrolyte/sulfur (E/S) ratio (4.0 µL mg −1 ), the S/LCO-HEO composite cathode shows desirable sulfur utilization and good cycle stability. This work demonstrates the feasibility of high entropy-driven multiple distinct functional polar sites for high-rate and long-cycle Li-S batteries.