High-entropy-induced strong dipole moment for accelerating sulfur reduction kinetics lithium-sulfur batteries across a wide range of temperatures

Abstract

Developing unexpected electrocatalysts is essential for lithium−sulfur batteries operating under harsh environmental conditions. Herein, a high−entropy−induced dipole moment enhancement strategy is proposed to address the problems related to complex temperature variations. In particular, a new platform corresponding to liquid-liquid conversion appears at low temperatures, considered as another rate-determining step. High−entropy oxide La_0.71Sr_0.29(Fe_0.19Co_0.20Ni_0.20Zn_0.19Mn_0.22)O_3−δ (HE−LSMO) nanosheets are synthesized by incorporating more metallic ions into LaSrMnO₃, which would increase the crystal asymmetry, create the redistribution of the electron cloud in the HE−LSMO, thereby enhancing dipole moments and strengthening the dipole−dipole interaction between HE−LSMOs and polar intermediate lithium polysulfides (LiPSs). The HE−LSMO can effectively adsorb LiPSs and greatly promote rapid conversions of LiPSs during the sulfur reduction process at a range of −35 to 50 °C. At 50 °C, the S/HE−LSMO cathode exhibits a high initial specific capacity of 1455.9 mAh g⁻¹ at 0.5 C, with a capacity retention rate of 71.1 % after 100 cycles. At −35 °C, the S/HE−LSMO cathode maintains an initial capacity of 740.7 mAh g⁻¹ at 0.5 C, with an impressive capacity retention of 90.4 % after 100 cycles. This work demonstrates the feasibility of the high−entropy−induced dipole moment enhancement strategy for lithium−sulfur batteries under wide temperatures.