Synergistic enhancement of Li-S battery low-temperature cycling performance by nano-sized uniformly compounded FeCoNi and MnO nanoparticles

Lithium-sulfur (Li-S) battery has high energy density, which demonstrated the potential to conquer the energy storage market. However, in cryogenic circumstances, due to polysulfides (LiPSs) clustering, slow electrochemical reaction, and serious polarization, commercial applications are seriously hindered. Previous works proved that alloy particles enable high-performance low-temperature Li-S batteries, nevertheless, the cycling stability is unsatisfactory due to the serious shuttle effect at low temperatures. Here, FeCoNi nanoparticles (NPs) were introduced as a catalyzer, benefiting from the structural and compositional merits it can synergistically catalyze more kinds of LiPSs. To enhance adsorption ability, MnO NPs were used to anchor LiPSs, thus providing a higher concentration of LiPSs around FeCoNi NPs and MnO NPs, thereby preventing the shuttle effect and enhancing cycling stability at low temperatures. Finally, a composite cathode material FCN-MO@CNFs was synthesized by one-step in-situ pyrolysis. Via detailed electrochemical analysis, FCN-MO@CNFs exhibited excellent electrocatalytic activity and achieved satisfactory low-temperature cycling performance. The initial discharge capacity reaches 1167.5 mAh g(-1) under 40 degrees C at 0.1C, and the capacity retention rate reaches 70.1 % after 100 cycles at 0.2C. This work provides a novel method for the practical development of high-performance low-temperature Li-S batteries.

Automated summary

This study introduces FeCoNi and MnO nanoparticles as catalysts and anchors to improve the low-temperature cycling stability of lithium-sulfur batteries. A composite cathode material FCN-MO@CNFs is synthesized by one-step in-situ pyrolysis, which exhibits excellent electrocatalytic activity and satisfactory low-temperature cycling performance.