Synergistic effect of sulfur-rich copolymer/S8 and carbon host porosity in Li-S batteries
Synergistic effect of sulfur-rich copolymer/S8 and carbon host porosity in Li-S batteries
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DOI：
10.1016/j.electacta.2020.137088
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发表时间：
2021
影响因子：
6.6
通讯作者：
A. Rafie;Arvinder Singh;V. Kalra
中科院分区：
文献类型：
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作者：
A. Rafie;Arvinder Singh;V. Kalra
在这项工作中，我们研究了当富硫共聚物用作正极中的活性成分时，主体材料孔隙率在Li-S电池性能中的可能作用。我们使用电纺碳纳米纤维（CNF）和聚（硫无规-1，3-二异丙烯基苯）/SDIB（具有一些残留的未反应硫）合成了独立式阴极材料，并且在不添加任何粘合剂或集流体的情况下使用它。为了研究CNF的孔隙率的影响，设计了两种不同的多孔样品，微孔（miCNF）和介孔（meCNF）。当使用miCNF作为主体材料时，容量在50次循环内稳定至577 mAh/g，并且保持稳定直至600次循环，其中沿着每循环0.046%的小容量衰减率，并且在整个600次循环中具有>98%的优异库仑效率。另一方面，SDIB-meCNF阴极提供约600 mAh/g的稳定容量，衰减可忽略不计。然而，稳定性仅持续了145次循环。尽管在SDIB活性材料中形成的C-S键具有积极作用，但我们假设阴极主体的孔隙率仍然起着重要作用，这不仅是由于原始阴极中残留的未反应的S8，而且还由于在循环过程中从C-S-Sn-S-C（SDIB）中的S-S键断裂出现的额外的松散的可溶性-Sn-链。此外，使用有效容量计算，我们将我们的阴极的放电容量与在C/2和C/5倍率下对富硫共聚物的其他工作进行了比较。有效容量分析清楚地表明了使用集流体和无粘合剂的静电纺丝CNF作为SDIB的主体基质的优点。
In this work, we investigate the possible role of host material porosity in performance of Li-S batteries, when sulfur-rich copolymer is used as an active ingredient in the cathode. We synthesized a freestanding cathode material using electrospun carbon nanofibers (CNFs) and poly(sulfur-random-1,3-diisopropenylbenzene)/SDIB (with some residual unreacted sulfur) and used it without adding any binders or current collectors. To study the effect of porosity of CNFs, two different porous samples, microporous (miCNF) and mesoporous (meCNF), were designed. When miCNF was used as a host material, the capacity stabilized to 577 mAh/g within 50 cycles and remained stable up to 600 cycles with a small capacity decay rate of 0.046% per cycle along with an excellent coulombic efficiency of >98% throughout the 600 cycles. On the other hand, SDIB-meCNF cathodes delivered a stable capacity of ~600 mAh/g with negligible decay. However, the stability only lasted for 145 cycles. Despite the positive effect of C-S bond formed in SDIB active material, we hypothesize that the porosity of the cathode host still plays a significant role not only due to residual unreacted S8in the original cathode, but also due to additional loose soluble -Sn- chains that emerge from S-S bond breakage in C-S-Sn-S-C (SDIB) over the course of cycling. Moreover, using the effective capacity calculation, we compared the discharge capacity of our cathode to other works on sulfur rich copolymers at C/2 and C/5 rates. The effective capacity analysis clearly manifests the advantages of using current-collector and binder-free electrospun CNFs as a host matrix for SDIB.