Sodium-metal sulfide battery holds great promise for sustainable and cost-effective applications. Nevertheless, achieving high capacity and cycling stability remains a great challenge. Here, uniform yolk-shell iron sulfide-carbon nanospheres have been synthesized as cathode materials for the emerging sodium sulfide battery to achieve remarkable capacity of ∼ 545 mA h g(-1) over 100 cycles at 0.2 C (100 mA g(-1)), delivering ultrahigh energy density of ∼ 438 Wh kg(-1). The proven conversion reaction between sodium and iron sulfide results in high capacity but severe volume changes. Nanostructural design, including of nanosized iron sulfide yolks (∼ 170 nm) with porous carbon shells (∼ 30 nm) and extra void space (∼ 20 nm) in between, has been used to achieve excellent cycling performance without sacrificing capacity. This sustainable sodium-iron sulfide battery is a promising candidate for stationary energy storage. Furthermore, this spatially confined sulfuration strategy offers a general method for other yolk-shell metal sulfide-carbon composites.

中文翻译：

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均匀的蛋黄壳硫化铁碳纳米球，用于优质的钠铁硫化物电池。

钠金属硫化物电池在可持续和具有成本效益的应用方面具有广阔的前景。然而，实现高容量和循环稳定性仍然是巨大的挑战。在这里，已经合成了均匀的蛋黄壳硫化铁碳纳米球作为新兴硫化钠电池的阴极材料，以在0.2 C（100 mA g（-1））的100个循环中实现约545 mA hg（-1）的显着容量。 ），可提供约438 Wh kg（-1）的超高能量密度。钠和硫化铁之间已证实的转化反应可产生高容量，但体积变化严重。纳米结构设计，包括具有多孔碳壳（〜30 nm）和介于两者之间的额外空隙空间（〜20 nm）的纳米级硫化铁蛋黄（〜170 nm），已在不牺牲容量的情况下实现了出色的循环性能。这种可持续发展的钠铁硫化物电池是固定能量存储的有前途的候选者。此外，这种空间受限的硫化策略为其他蛋黄壳金属硫化物-碳复合材料提供了一种通用方法。