Molecular‐Level Design of Pyrrhotite Electrocatalyst Decorated Hierarchical Porous Carbon Spheres as Nanoreactors for Lithium–Sulfur Batteries |
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Authors: | Yash Boyjoo Haodong Shi Emilia Olsson Qiong Cai Zhong‐Shuai Wu Jian Liu Gao Qing Lu |
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Affiliation: | Yash Boyjoo,Haodong Shi,Emilia Olsson,Qiong Cai,Zhong‐Shuai Wu,Jian Liu,Gao Qing (Max) Lu |
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Abstract: | 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 m2 g?1), large pore volume (0.41 cm3 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. |
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Keywords: | electrocatalytic effects lithium– sulfur batteries metal sulfides porous carbon spheres pyrrhotite |
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