Due to its high reversible capacity, Fe7S8 has emerged as a promising anode material for sodium-ion batteries (SIBs). However, its application is limited by slow reaction kinetics and significant volume expansion during the charging and discharging process, resulting in poor rate capacity and reduced cycling stability. To address these issues, a novel high-temperature gas-expansion method is proposed to uniformly incorporate Fe7S8 nanoparticles into N and S co-doped porous carbon (Fe7S8@NSC). It effectively reduces the volume expansion of Fe7S8 and improves its electron/ion conductivity. As a result, when used as an anode material in SIBs, Fe7S8@NSC demonstrates excellent rate performance, delivering a capacity of 500.0 mAh/g at a current density of 5 A/g. Additionally, it exhibits remarkable stability, maintaining 99.83 % of its capacity after 600 cycles at the same high current density.

中文翻译：

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用于同步 Fe7S8@NSC 负极高速和超稳定钠存储的气体膨胀策略


由于其高可逆容量，Fe7S8 已成为一种很有前途的钠离子电池 （SIB） 负极材料。然而，其应用受到缓慢反应动力学和充放电过程中显着体积膨胀的限制，导致倍率容量差和循环稳定性降低。为了解决这些问题，提出了一种新的高温气体膨胀方法，将 Fe7S8 纳米颗粒均匀地掺入 N 和 S 共掺杂多孔碳 （Fe7S8@NSC） 中。它有效地降低了 Fe7S8 的体积膨胀，提高了其电子/离子电导率。因此，当用作 SIB 中的负极材料时，Fe7S8@NSC表现出优异的倍率性能，在 5 A/g 的电流密度下提供 500.0 mAh/g 的容量。此外，它还表现出卓越的稳定性，在相同的高电流密度下，经过 600 次循环后仍能保持 99.83% 的容量。