In-situ Formed Polar Fe2N/MCMB Hybrid Interlayer for High-Rate Li–S Batteries,Energy & Fuels

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In-situ Formed Polar Fe2N/MCMB Hybrid Interlayer for High-Rate Li–S Batteries
Energy & Fuels ( IF 5.2 ) Pub Date : 2021-10-14 , DOI: 10.1021/acs.energyfuels.1c02504
Nagalakshmi Muralidharan _{1,

2} , Kalaiselvi Nallathamby _{1,

2}

Affiliation

Owing to its high theoretical capacity (1675 mA h g^–1) and high theoretical energy density (2600 W h kg^–1), lithium–sulfur (Li–S) batteries receive intense attention as an alternate to current lithium-ion batteries (LIBs). Sulfur, a surplus byproduct from petroleum industry along with an earth-abundant nature, ensures the low-cost production of Li–S batteries compared to LIBs. However, the common technical hurdles associated with sulfur such as low conductivity and poor cyclability due to the polysulfide shuttling effect hinder the realistic applications. In the current work, cashewnut sheath-derived biocarbon (CNS) is utilized as a host material for sulfur cathodes, in order to enhance the conductivity and to realize better electrochemical performance, especially at low current rates. For instance, a 50 wt % sulfur-loaded CNS cathode (CNS50S) shows a high specific capacity of 680 mA h g^–1 at C/10 rate even after 700 cycles with a gravimetric energy density of 415 W h kg^–1. When the in situ formed polar Fe₂N/MCMB was introduced as an interlayer, excellent electrochemical performance is obtained for CNS@SS cathodes even at high rates due to the effective mitigation of lithium polysulfide dissolution and efficient reutilization of absorbed polysulfides on the interlayer surface. For example, CNS50SIL and CNS60SIL cathodes deliver a specific capacity of 343 and 518 mA h g^–1 at a high rate of 1C even after 120 cycles, respectively. This study offers ample scope to exploit CNS@SS composite cathodes for real-time applications and throws light on the importance of custom-designed Fe-based polar interlayers in improving the electrochemical behavior of Li–S batteries in terms of capacity at high rates.

中文翻译：

用于高倍率锂硫电池的原位形成的极性 Fe2N/MCMB 混合中间层

由于其高理论容量 (1675 mA hg ^–1 ) 和高理论能量密度 (2600 W h kg ^–1)，作为当前锂离子电池 (LIB) 的替代品，锂硫 (Li-S) 电池受到广泛关注。与 LIB 相比，硫是石油工业的一种过剩副产品，而且地球资源丰富，确保了 Li-S 电池的低成本生产。然而，由于多硫化物穿梭效应，与硫相关的常见技术障碍，如低导电性和循环性差，阻碍了实际应用。在目前的工作中，腰果鞘衍生的生物碳（CNS）被用作硫正极的主体材料，以提高导电性并实现更好的电化学性能，尤其是在低电流速率下。例如，50 wt% 硫负载的 CNS 正极 (CNS50S) 显示出 680 mA hg ^–1的高比容量即使在 415 W h kg ^–1的重量能量密度下，在 700 次循环后仍以 C/10 速率运行。当原位形成的极性 Fe ₂ N/MCMB 作为夹层引入时，由于有效减缓多硫化锂溶解和有效再利用夹层表面吸附的多硫化物，即使在高倍率下，CNS@SS 正极也能获得优异的电化学性能. 例如，CNS50SIL 和 CNS60SIL 阴极的比容量为 343 和 518 mA hg ^–1即使在 120 次循环后，仍保持 1C 的高速率。这项研究为利用 CNS@SS 复合阴极进行实时应用提供了充足的空间，并阐明了定制设计的 Fe 基极性夹层在提高 Li-S 电池在高倍率容量方面的电化学行为的重要性。

更新日期：2021-11-04

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