Interwoven n-doped bimetallic/carbon nanosheets as an efficient electrocatalyst for wide-temperature lithium-sulfur batteries

Lithium-sulfur batteries (LSBs), possessing high theoretical energy density are recognized as one of the most exciting rechargeable cells. Unfortunately, the actual application of LSBs significantly hindered by the shuttle effect of lithium polysulfides (LiPSs) and sluggish kinetics of the sulfidation reaction, resulting in suboptimal performance over a broad temperature range. Herein, an efficient electrocatalyst with hierarchical porous structure and a large specific surface area (denoted Fe/Ni-N@NC) is devised and applied for wide-temperature LSBs. The unique structure of this electrocatalyst exposes abundant bimetal (M1/M2-Nx) and nitrogen-active sites, which accelerates the rapid conversion of LiPSs at low temperatures and effectively mitigates the shuttle effect at elevated temperatures. Consequently, the Fe/Ni-N@NC-modified cell demonstrates upgraded performances over a wide-temperature range (0 ∼ 65 °C). Additionally, the modified cell demonstrated exceptional long-term cycling stability (with a decay rate of only 0.062 % among 1000 cycles at 1 C), excellent rate capability (achieving 812 mAh/g at 4.0 C), and remarkable resistance to self-discharge (with a capacity decay of merely 3.9 % over one week). These findings may guide the design of porous bimetallic electrocatalysts for wide-temperature LSBs.