Abstract Reasonable design of porous biochar materials with good conductivity, excellent sulfur dispersion, strong adsorption ability to polysulfides (LiPSs), low cost and comprehensive performance is proper way for solving the problem of ‘shuttle effect’ of lithium sulfur battery (Li-S battery). Herein, a novel facile strategy, utilizing potassium ferrate (K2FeO4), to fulfill the synchronous carbonization and iron carbide (Fe3C) doping of folium cycas to prepare Fe3C nano-particles/porous biochar (Fe3C/PB) composite materials is proposed. The as-prepared Fe3C/PB samples possess a porous structure with a large specific surface area (2732.3 m2 g-1) and a cumulative pore volume of 1.6 cm3 g-1, in which Fe3C plays a key role in electronic transmission, LiPSs adsorption and conversion in Li-S battery. After sulfur infusion, the Fe3C/PB@S composite with 69.6 wt% sulfur loading exhibits the highest initial discharge capacity of 1347.7 mA h g-1 at the rate of 1 C. It is stable at 837.6 mA h g-1 after 5 cycles, and is capable to maintain at 555.3 mA h g-1 even after 250 cycles. The rational design of porous structural biochar materials with Fe3C doping is of great significance to achieve low-cost, green and large-scale production to improve the electrochemical performance of Li-S battery and promote the industrial applications.

中文翻译：

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锂硫电池Fe3C纳米颗粒/多孔生物炭正极材料的简便合成

摘要 合理设计导电性好、硫分散性好、对多硫化物（LiPSs）吸附能力强、成本低、综合性能好的多孔生物炭材料是解决锂硫电池（Li-S电池）“穿梭效应”问题的正确途径。 ）。在此，提出了一种利用高铁酸钾 (K2FeO4) 实现苏铁叶同步碳化和碳化铁 (Fe3C) 掺杂制备 Fe3C 纳米颗粒/多孔生物炭 (Fe3C/PB) 复合材料的新策略。所制备的 Fe3C/PB 样品具有多孔结构，具有较大的比表面积 (2732.3 m2 g-1) 和 1.6 cm3 g-1 的累积孔体积，其中 Fe3C 在电子传输、LiPSs 吸附中起关键作用和锂硫电池的转换。注入硫磺后，具有 69.6 wt% 硫负载的 Fe3C/PB@S 复合材料在 1 C 倍率下表现出最高的初始放电容量 1347.7 mAh g-1。5 个循环后稳定在 837.6 mAh g-1，并且即使在 250 次循环后仍保持在 555.3 mAh g-1。合理设计掺杂Fe3C的多孔结构生物炭材料对于实现低成本、绿色、规模化生产，提高锂硫电池电化学性能，促进工业应用具有重要意义。