Controllable Substitution of S Radicals on Triazine Covalent Framework to Expedite Degradation of Polysulfides,Small

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Controllable Substitution of S Radicals on Triazine Covalent Framework to Expedite Degradation of Polysulfides
Small ( IF 13.0 ) Pub Date : 2020-11-30 , DOI: 10.1002/smll.202004631
Yingchun Yan ₁ , Zhou Chen ₁ , Jun Yang ₁ , Lu Guan ₁ , Han Hu ₁ , Qingshan Zhao ₁ , Hao Ren ₁ , Yan Lin ₁ , Zhongtao Li ₁ , Mingbo Wu ₁

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Lithium–sulfur (Li–S) batteries are facing a significant barrier due to the diffusion of intermediate redox species. Although some S doped covalent framework cathodes have been reported with outstanding reversibility, the low content of sulfur (less than 30%) limits the practical applications. To overcome the issue, the sulfur and nitrogen co‐doped covalent compounds (S‐NC) as a host‐type cathode have been developed through the radical transfer process during thermal cracking amino groups on the precursor, and then plentiful positively charged sulfur radicals can be controllably introduced. The experimental characterization and DFT theoretical calculation certificate that the sulfur radicals in S‐NC/S can expedite redox reactions of intermediate polysulfides to impede their dissolution. Moreover, the energy barriers during ions transfer also obviously decreased after introducing S radicals, which lead to improved rate performance.

中文翻译：

在三嗪共价骨架上可控地取代S自由基以加速多硫化物的降解

锂-硫（Li-S）电池由于中间氧化还原物质的扩散而面临着重大障碍。尽管已报道一些掺S的共价骨架阴极具有出色的可逆性，但硫的含量低（少于30％）限制了实际应用。为了解决这个问题，在前体上的氨基热裂化过程中，通过自由基转移过程开发了硫和氮共掺杂共价化合物（S-NC）作为主体型阴极，然后可以将大量带正电的硫自由基被可控地介绍。实验表征和DFT理论计算证明，S-NC / S中的硫自由基可加速中间多硫化物的氧化还原反应，从而阻止其溶解。此外，

更新日期：2020-12-22

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