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A freestanding hierarchically structured cathode enables high sulfur loading and energy density of flexible Li–S batteries
Journal of Materials Chemistry A ( IF 11.9 ) Pub Date : 2020/02/28 , DOI: 10.1039/c9ta14240a
Jianpeng Liu 1, 2, 3, 4 , Zhong Li 1, 2, 3, 4 , Beibei Jia 1, 2, 3, 4 , Juncheng Zhu 4, 5, 6, 7 , Wenliang Zhu 8, 9, 10, 11 , Jianping Li 4, 12, 13, 14 , Hao Pan 4, 12, 13, 14 , Bowen Zheng 1, 2, 3, 4 , Liangyin Chen 2, 3, 4, 15 , Giuseppe Pezzotti 8, 9, 10, 11 , Jiliang Zhu 1, 2, 3, 4
Affiliation  

Due to sulfur agglomeration and drastic volume expansion during charging, a significant challenge for lithium–sulfur battery applications is to achieve favorable energy densities while realizing substantial sulfur loading. The rational design of cathode materials is therefore essential. Here we show a new type of low-cost sulfur/silica/carbon hybrid cathode by integrating carbon-coated and sulfur-encapsulated mesoporous SiO2 nanospheres with a carbon fiber cross-linked graphene framework (denoted as 3D-GCSS). The porous morphology of SiO2 ensures electrolyte accessibility, while the mechanical robustness of graphene and the carbon fiber contributes to structural sturdiness and flexibility. The synergistic effect exerted by polar SiO2 together with conductive graphene and the carbon fiber helps to confine sulfur and intermediate polysulfides as well as providing abundant charge transfer paths. Benefiting from these merits, a coin cell fabricated based on the freestanding 3D-GCSS with an 8 mg cm−2 sulfur content displayed a high capacity of 1462 mA h g−1 at 0.5C, satisfactory rate performance and cycling stability. More importantly, a type of ultra-flexible soft-packaged cell was assembled utilizing the 3D-GCSS electrode. At a considerable sulfur loading of 20 mg cm−2, the battery delivered an outstanding capacity of 2.15 A h, a gravimetric energy density of 371 W h kg−1 (1055 W h kg−1 based on the cathode) and a volumetric energy density of 582 W h l−1.

中文翻译:

独立的分层结构阴极可实现高柔性锂电池的高硫负荷和能量密度

由于充电过程中硫的结块和体积的急剧膨胀,锂硫电池应用面临的一项重大挑战是在实现理想的能量密度的同时实现大量的硫负载。因此,阴极材料的合理设计至关重要。在这里,我们通过将碳包膜和硫包封的介孔SiO 2纳米球与碳纤维交联的石墨烯骨架(表示为3D-GCSS)集成在一起,展示了一种新型的低成本硫/二氧化硅/碳杂化阴极。SiO 2的多孔形态确保了电解液的可及性,而石墨烯和碳纤维的机械坚固性有助于结构坚固性和柔韧性。极性SiO 2产生的协同效应与导电石墨烯和碳纤维一起,有助于限制硫和中间多硫化物,并提供丰富的电荷转移路径。受益于这些优点,基于独立的3D-GCSS制成的纽扣电池具有8 mg cm -2的硫含量,在0.5C时显示出1462 mA hg -1的高容量,令人满意的倍率性能和循环稳定性。更重要的是,利用3D-GCSS电极组装了一种超柔性软包装电池。在20 mg cm -2的相当大的硫负荷下,电池的输出容量为2.15 A h,重量能量密度为371 W h kg -1(1055 W h kg -1(基于阴极)和582 W hl -1的体积能量密度。
更新日期:2020-04-01
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