Insight into the Function Mechanism of the Carbon Interlayer in Lithium-Sulfur Batteries

Abstract

The carbon-based interlayers set between the sulfur cathode and the separator have been demonstrated to be a simple but powerful means to promote the electrochemical performances of the Li-S batteries. However, the detailed mechanism has yet been fully understood. In this work, a series of battery configurations have been designed to further analyze the function mechanism of the carbon interlayer. The controlled studies demonstrate that the function of the interlayer as an accessorial current collector to provide and transport electrons plays the most important role in enhancing the dischargeability and reversibility of the sulfur cathode. The fundamental understanding of the function mechanism will provide further insight for the rational design of the interlayer structure in the Li-S battery system.

Advances in Lithium–Sulfur Batteries: From Academic Research to Commercial Viability

“…h-k) Reproduced with permission. [210] Copyright 2018, The Electrochemical Society. and Celgard separator, in which the carbon interlayer has an electrical contact with the cathode.…”

“…To gain more understanding on the role of carbon interlayer (Figure 29h,i), Huang and co‐workers designed a series of battery configurations to further analyze the function mechanism in Li–S batteries (Figure 29j). [ 210 ] Configuration A shows the routine Li–S battery without carbon interlayer. Configuration B shows a carbon interlayer inserted between the cathode and Celgard separator, in which the carbon interlayer has an electrical contact with the cathode.…”

“…k) Cycling performances and Coulombic efficiencies of Li-S cells with four different battery configurations. h-k) Reproduced with permission [210]. Copyright 2018, The Electrochemical Society.…”

Synergistic improvement of the overall performance of lithium-sulfur batteries

“…本课题组 [86] 还通过简单的两步加热方法，实现了 S 与异氰脲酸三烯丙基的开环共 聚，合成出了一种高硫含量(90%)且具有独特两相结构的 S-三烯丙基异氰脲酸酯有机硫 聚合物复合材料(STI)。该复合材料具有类似"西瓜"的结构：单斜 S 纳米晶体作为"西瓜 籽"嵌入在有机硫聚合物非晶基体中。其中，单斜相可以为离子扩散提供更多的空间， 有助于加快锂化/脱锂化过程的动力学 [87,88] [90] Figure 7 Research on working mechanism of modifying layer. (a) Schematic illustration for the fabrication of different electrode configurations [89] .…”

“…(b) Cycling performance and Coulombic efficiency curves of HPC/S cathode and HPC@SnO 2 /S cathode (configuration I) at 0.2 C [89] . Illustration (c) and cycling performance (d) of four different battery configurations [90] 有关功能性中间层的研究工作被争相报道，但对于该结构的作用机理并未得到 深入的研究。因此，我们在上述工作的基础上，进一步研究了功能性中间层结构的作 用机理 [90] 的锂沉积/溶出能力，并大大提高了库仑效率 [97] 。 本课题组 [98] 还提出了一种通过疏浚、阻拦相结合来控制锂离子转向的负极保护新 策略。如图 8a 所示，嵌入金纳米粒子(Au)的碳纳米纤维(CFs)被固定在远离隔膜的一侧， 负极的 Li-S 全电池循环性能对比图 [99] Figure 8 Suppression of lithium dendrites through constructing three dimensional collector. (a)…”