Li-S battery as an alternative to next-generation battery systems suffers from electrical insulating properties of sulfur, “shuttle effects” and slow kinetics of lithium polysulfides (LiPSs). Separator modification via catalysts with multiple scales of active sites are great potential; however, the preparation of such a kind of catalysts is still complex and tedious. Here, we developed a facile pyrolysis strategy to fabricate multiple Fe active sites on N-doped porous graphitized carbon nanosheets (Fe-NG) from Chlorella, including atomically dispersed Fe single atoms, Fe nanoclusters and carbon-coated Fe nanoparticles, which enhanced the affinity to LiPSs and accelerated their conversion kinetics. As Fe-NG was utilized to modify the separators, the resulting Li-S battery demonstrated an initial discharge capacity of 1062.1 mAh g−1 at 1 C and maintained at 678 mAh g−1 after 500 cycles with the average capacity decay rate of 0.072 % per cycle. This work provides a rational design and large-scale preparation routes for separator modifying catalysts with heterogeneous active species on biomass-derived carbons.

中文翻译：

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利用小球藻轻松合成具有多个铁活性位点的石墨化碳纳米片，以改进高效锂硫电池的隔膜


锂硫电池作为下一代电池系统的替代品，受到硫的电绝缘特性、“穿梭效应”和多硫化锂 (LiPS) 缓慢动力学的影响。通过具有多种活性位点的催化剂对分离器进行改造具有巨大的潜力；然而，此类催化剂的制备仍然复杂、繁琐。在这里，我们开发了一种简便的热解策略，在小球藻的氮掺杂多孔石墨化碳纳米片（Fe-NG）上制造多个铁活性位点，包括原子分散的铁单原子、铁纳米团簇和碳包覆的铁纳米颗粒，从而增强了亲和力LiPS 并加速其转化动力学。由于采用Fe-NG对隔膜进行改性，所得的Li-S电池在1 C下的初始放电容量为1062.1 mAh g−1，并在500次循环后保持在678 mAh g−1，平均容量衰减率为0.072每个周期的百分比。这项工作为生物质衍生碳上具有非均相活性物质的分离器改性催化剂提供了合理的设计和大规模制备路线。