Room-temperature sodium–sulfur (RT Na–S) batteries are widely considered as one of the alternative energy-storage systems with low cost and high energy density. However, the both poor cycle stability and capacity are two critical issues arising from low conversion kinetics and sodium polysulfides (NaPSs) dissolution for sulfur cathodes during the charge/discharge process. Herein, we report a highly stable RT Na–S battery cathode via building heterostructures in multichannel carbon fibers. The TiN-TiO₂@MCCFs, fabricated by electrospinning and nitriding techniques, are loaded with the active material S, forming S/TiN-TiO₂@MCCFs as the cathode in a RT Na–S battery. At 0.1 A g^–1, the cathode produces the capacity of more than 640 mAh g^–1 within 100 cycles with a high Coulombic efficiency of nearly 100%. Even at 5 A g^–1, the battery still exhibites a capacity of 257.1 mAh g^–1 after 1000 cycles. Combining structural and electrochemical analyses with the first-principles calculations reveals that the incorporation of the highly electrocatalytic activity of TiN with the powerful chemisorption of TiO₂ well stabilizes S and also alleviates the shuttle effects of polysulfides. This work with simple processes and low cost is expected to promote the further development and application of metal–S batteries.

中文翻译：

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通过在多通道碳纤维中构建异质结构来实现稳定的室温钠硫电池阴极

室温钠硫（RT Na–S）电池被广泛认为是低成本和高能量密度的替代储能系统之一。然而，不良的循环稳定性和容量都是由于低转化动力学和在充电/放电过程中硫阴极溶解多硫化钠（NaPS）引起的两个关键问题。在这里，我们通过在多通道碳纤维中建立异质结构报告了高度稳定的RT Na–S电池阴极。通过静电纺丝和氮化技术制造的TiN-TiO ₂ @MCCFs负载有活性物质S，在RT Na–S电池中形成S / TiN-TiO ₂ @MCCFs作为阴极。在0.1 A g ^–1时，阴极产生的容量超过640 mAh g在100个循环中^–1，库仑效率接近100％。即使在5 A g ^–1下，经过1000次循环后，电池仍显示257.1 mAh g ^–1的容量。将结构和电化学分析与第一性原理计算相结合，发现将TiN的高电催化活性与TiO _2的强化学吸附相结合，可以很好地稳定S并减轻多硫化物的穿梭效应。这项工艺简单，成本低的工作有望促进金属S电池的进一步开发和应用。