A Freestanding Flexible Single‐Atom Cobalt‐Based Multifunctional Interlayer toward Reversible and Durable Lithium‐Sulfur Batteries,Small Methods

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A Freestanding Flexible Single‐Atom Cobalt‐Based Multifunctional Interlayer toward Reversible and Durable Lithium‐Sulfur Batteries
Small Methods ( IF 10.7 ) Pub Date : 2020-01-27 , DOI: 10.1002/smtd.201900701
Yiju Li ₁ , Peng Zhou ₁ , Hui Li ₂ , Tingting Gao ₃ , Lei Zhou ₁ , Yelong Zhang ₁ , Ni Xiao ₁ , Zhonghong Xia ₁ , Liang Wang ₁ , Qinghua Zhang ₄ , Lin Gu ₄ , Shaojun Guo _{1,

5}

Affiliation

The development of Li‐S batteries is greatly hindered by the polysulfide shuttling and sluggish sulfur redox kinetics, leading to low utilization of active materials and rapid capacity decay. Herein, a freestanding multifunctional interlayer, prepared by layer‐by‐layer assembling of the single‐atom cobalt‐anchored nitrogen‐doped carbon nanosheets (NC@SA‐Co) and dual network of carbon nanotube‐cellulose nanofiber (CNT‐CNF) hybrid, is proposed to effectively enhance the polysulfide immobilization and sulfur redox kinetics. The conductive CNT network acts as the physical barrier to confine the polysulfide diffusion and to facilitate the reuse of polysulfides. The oxygen‐group‐terminated CNF network allows the hopping of Li⁺ ion and suppresses the polysulfide crossover due to the strong electrostatic repulsion. Moreover, it is demonstrated that the 2D NC@SA‐Co with numerous well‐defined single sites of Co–N₄ can effectively serve as an electrocatalyst to boost the reversible reaction of polysulfides. As a result, the assembled Li‐S batteries with the multifunctional interlayer deliver a high reversible specific capacity of 1160 mAh g⁻¹ at 0.1 C and an ultralow capacity decay of 0.058% per cycle over 700 cycles. Even with a high sulfur loading of 7.2 mg cm⁻², a high areal capacity of 8.3 mAh cm⁻² can be achieved.

中文翻译：

独立的，灵活的单原子钴基多功能中间层，可逆转和耐用的锂硫电池

多硫化物的穿梭和硫氧化还原动力学的迟缓极大地阻碍了锂电池的发展，导致活性材料利用率低和容量衰减迅速。在此，通过单层钴锚定氮掺杂碳纳米片（NC @ SA-Co）和碳纳米管-纤维素纳米纤维（CNT-CNF）杂物的双网络的逐层组装制备了一个独立的多功能中间层。提出，以有效地增强多硫化物的固定化和硫的氧化还原动力学。导电CNT网络充当限制多硫化物扩散并促进多硫化物再利用的物理屏障。端氧基团的CNF网络允许Li ⁺跳跃离子并抑制由于强静电排斥而引起的多硫化物交叉。此外，已证明具有许多明确定义的Co-N ₄单点的2D NC @ SA-Co可以有效地用作促进多硫化物可逆反应的电催化剂。结果，组装好的具有多功能夹层的Li‐S电池在0.1 C下可提供1160 mAh g ^-1的高可逆比容量，并且在700个循环中每个循环的超低容量衰减为0.058％。即使具有7.2mg cm ^-2的高硫负载，也可以实现8.3mAh cm ^-2的高面积容量。

更新日期：2020-01-27

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