Molecular-Level Design of Pyrrhotite Electrocatalyst Decorated Hierarchical Porous Carbon Spheres as Nanoreactors for Lithium-Sulfur Batteries
Molecular-Level Design of Pyrrhotite Electrocatalyst Decorated Hierarchical Porous Carbon Spheres as Nanoreactors for Lithium-Sulfur Batteries
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DOI：
10.1002/aenm.202000651
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发表时间：
2020-04-16
影响因子：
27.8
通讯作者：
Lu, Gao Qing (Max)
中科院分区：
文献类型：
--
作者：
Boyjoo, Yash;Shi, Haodong;Lu, Gao Qing (Max)
锂硫电池（LSB）是一类新一代可充电高能量密度电池。然而，多硫化锂（LiP）溶解的持续问题和阻碍LSB效率的穿梭效应是解决的挑战。本文提出了一种将磁黄铁矿Fe 1-xS纳米粒子嵌入多级多孔氮掺杂碳球（Fe 1-xS-NC）中的通用合成方法。Fe 1-xS-NC具有高比表面积（627 m2 g-1）、大孔体积（0.41 cm 3 g-1）以及增强的吸附和向LiPs的电催化转变。此外，碳球内原位生成的大中孔可以容纳高达75%的高硫负载，并在充电/放电循环期间维持体积变化以及改善离子/质量传递。理论预测和实验证实了Fe_（1-x）S-NC对LiPs的特殊吸附性能。随后，对Fe_（1-x）S-NC的电催化活性进行了全面的验证。结果证实Fe 1-xS-NC是一种高效的硫负载纳米反应器。因此，Fe 1-xS-NC纳米反应器作为LSB的阴极材料表现得非常好，表现出1070 mAh g（-1）的高初始容量，在0.5 C下200次循环后几乎没有容量损失。此外，即使在8.14 mg cm（-2）的高硫负载下，所得LSB也显示出显著增强的倍率性能和循环性能。
Lithium-sulfur batteries (LSBs) are a class of new-generation rechargeable high-energy-density batteries. However, the persisting issue of lithium polysulfides (LiPs) dissolution and the shuttling effect that impedes the efficiency of LSBs are challenging to resolve. Herein a general synthesis of highly dispersed pyrrhotite Fe1-xS nanoparticles embedded in hierarchically porous nitrogen-doped carbon spheres (Fe1-xS-NC) is proposed. Fe1-xS-NC has a high specific surface area (627 m(2) g(-1)), large pore volume (0.41 cm(3) g(-1)), and enhanced adsorption and electrocatalytic transition toward LiPs. Furthermore, in situ generated large mesoporous pores within carbon spheres can accommodate high sulfur loading of up to 75%, and sustain volume variations during charge/discharge cycles as well as improve ionic/mass transfer. The exceptional adsorption properties of Fe1-xS-NC for LiPs are predicted theoretically and confirmed experimentally. Subsequently, the electrocatalytic activity of Fe1-xS-NC is thoroughly verified. The results confirm Fe1-xS-NC is a highly efficient nanoreactor for sulfur loading. Consequently, the Fe1-xS-NC nanoreactor performs extremely well as a cathodic material for LSBs, exhibiting a high initial capacity of 1070 mAh g(-1) with nearly no capacity loss after 200 cycles at 0.5 C. Furthermore, the resulting LSBs display remarkably enhanced rate capability and cyclability even at a high sulfur loading of 8.14 mg cm(-2).