Shi Junye, Khan Nimra, Gao Ning, Yu Chenxi, Li Bao, Wang Bao, Zheng Shumin
Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200433, China.
State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
ACS Appl Mater Interfaces. 2024 Aug 14;16(32):42312-42320. doi: 10.1021/acsami.4c09360. Epub 2024 Jul 30.
At low temperatures, lithium-sulfur (Li-S) batteries have poor kinetics, resulting in extreme polarization and decreased capacity. In this study, we investigated the electrochemical performance of Li-S batteries utilizing transition metal alloy-based cathode materials. Specifically, binary transition metal alloys (FeNi, FeCo, and NiCo) are integrated into a porous carbon nanofiber (CNF) matrix as composite cathode material. Our findings reveal that alloying metallic Ni with Fe in the FeNi@CNFs composite enhances the catalytic conversion of sulfur species, mitigating the shuttle effect and improving battery performance even under low temperatures. Li-S batteries employing a LiS/FeNi@CNFs cathode exhibited a significantly high initial discharge capacity of 1655 mAh g at 0.1 C. Even at the higher current density of 10 C, the LiS/FeNi@CNFs composite can still reach an ultrahigh specific capacity of 828 mAh g. In addition, LiS/FeNi@CNFs demonstrated exceptional initial discharge capacities of 890.5 and 382.7 mAh g at 0.1 C under -20 and -40 °C, respectively. With an initial capacity of 392.02 mAh g and a capacity retention rate of 88.86% (after 60 cycles) at 0.2 C, the conversion of LiPSs in LiS/FeNi@CNFs is significantly enhanced even at ultralow temperatures of -40 °C. The findings of this study hold significant implications for the advancement of extremely low-temperature Li-S batteries.
在低温下，锂硫（Li-S）电池动力学性能较差，导致极端极化和容量下降。在本研究中，我们研究了使用基于过渡金属合金的阴极材料的Li-S电池的电化学性能。具体而言，二元过渡金属合金（FeNi、FeCo和NiCo）被整合到多孔碳纳米纤维（CNF）基质中作为复合阴极材料。我们的研究结果表明，在FeNi@CNFs复合材料中，将金属Ni与Fe合金化可增强硫物种的催化转化，减轻穿梭效应，甚至在低温下也能提高电池性能。采用LiS/FeNi@CNFs阴极的Li-S电池在0.1 C时表现出高达1655 mAh g的显著高初始放电容量。即使在10 C的较高电流密度下，LiS/FeNi@CNFs复合材料仍能达到828 mAh g的超高比容量。此外，LiS/FeNi@CNFs在-20和-40 °C下于0.1 C时分别表现出890.5和382.7 mAh g的优异初始放电容量。在0.2 C时，LiS/FeNi@CNFs的初始容量为392.02 mAh g，容量保持率为88.86%（60次循环后），即使在-40 °C的超低温下，LiS/FeNi@CNFs中多硫化锂的转化也显著增强。本研究结果对极低温Li-S电池的发展具有重要意义。
