Plane Double-Layer Structure of AC@S Cathode Improves Electrochemical Performance for Lithium-Sulfur Battery

Abstract

Due to the high theoretical specific capacity of lithium-sulfur batteries, it is considered the most promising electrochemical energy storage device for the next generation. However, the development of lithium-sulfur battery has been restricted by its low cycle efficiency and low capacity. We present a Plane double-layer structure of AC@S cathode to improve the electrochemical performance of lithium-sulfur batteries. The battery with this cathode showed good electrochemical performance. The initial discharge capacity of the battery with the structure of AC@S cathode could reach 1,166 mAhg−1 at 0.1 C. After 200 cycles, it still remains a reversible capacity of 793 mAh g−1 with a low fading rate of 0.16% per cycle. Furthermore, the batteries could hold a discharge capacity of 620 mAh g−1 after 200 cycles at a typical 0.5 C rate. The improvement of electrochemical performance is attributed to that the polysulfide produced during charge/discharge can be better concentrated in the cathode by the planar double-layer structure, thus reducing the loss of sulfur.

Aqueous Quaternary Polymer Binder Enabling Long-Life Lithium–Sulfur Batteries by Multifunctional Physicochemical Properties

“…42 The Nyquist plot is composed of a low-frequency band sloping line (the Warburg impedance) and a medium−high frequency band semicircle, which is known as the charge transfer resistance (R CT ). 43,44 In this study, the R CT values of the Li−S|CMC− SBR and Li−S|PEI−PVP cells (Figure 4h,i) gradually increase with the number of cycles. Theoretically, the charging process would oxidize the insulating Li 2 S/Li 2 S 2 to the soluble LiPS; however, a small amount remains even after a full recharge.…”

“…In terms of EIS, impedance profiles separate individual electrochemical processes, enabling qualitative analysis of electron and mass transport, , which generally involves assessing the shape of Nyquist plot features to determine the different physicochemical processes in the cells . The Nyquist plot is composed of a low-frequency band sloping line (the Warburg impedance) and a medium–high frequency band semicircle, which is known as the charge transfer resistance ( R CT ). , In this study, the R CT values of the Li–S|CMC–SBR and Li–S|PEI–PVP cells (Figure h,i) gradually increase with the number of cycles. Theoretically, the charging process would oxidize the insulating Li 2 S/Li 2 S 2 to the soluble LiPS; however, a small amount remains even after a full recharge.…”

Electrospun 3D Structured Carbon Current Collector for Li/S Batteries

“…This could be related with PVdF binder used in cathode preparation, which led to the agglomeration of the irreversible Li2S2/Li2S phase with increasing cycles as explained in literature [58]. The existing void space between nanofibers provides extra space for intermediate products and inhibit the shuttle effect during reaction as mentioned above in the electrochemical performance test results [59].…”

Hierarchical Porous Graphene Bubbles as Host Materials for Advanced Lithium Sulfur Battery Cathode

“…However, the insulation nature of active sulfur materials, the severe shuttle effect of the soluble intermediate (Li 2 S x , 8 ≥ x ≥ 3), and the expansion and shrinking (around 80%) during the charge/discharge process actually will cause some fatal problems, including low utilization coefficient of sulfur and inferior Columbic efficiency (CE) accompanied with rapid capacity fading, which definitively hampers the practical applications of lithium sulfur (Li-S) batteries (Seh et al, 2013 ; Wei Seh et al, 2013 ; Li et al, 2016 ; Xu et al, 2020 ). To achieve an advanced Li-S system with stable electrochemical performances, extensive research efforts have been exploited in enhancing the integrated conductivity of cathode and developing an efficient host to confine polysulfides (Yin et al, 2012 ; Liu et al, 2017 ; Tao et al, 2018 ). Researchers have proposed significant strategies to improve the conductivity in cathode by introducing highly conductive carbon matrix (e.g.…”