Cationic Cyclopropenium-Based Hyper-Crosslinked Polymer Enhanced Polyethylene Oxide Composite Electrolyte for All-Solid-State Li-S Battery.

Shuang Lian,Yi Feng,Haifeng Ji,Xiaojie Zhang,Jingjing Shi,Yu Wang,Xiongwei Qu

doi:10.3390/nano11102562

Shuang Lian, Yi Feng + Show 5 more

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https://doi.org/10.3390/nano11102562

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Journal: Nanomaterials	Publication Date: Sep 29, 2021
Citations: 4	License type: CC BY 4.0

Affiliation: Hebei University of Technology, Nantong University

Abstract

The development of solid-state polymer electrolytes is an effective way to overcome the notorious shuttle effect of polysulfides in traditional liquid lithium sulfur batteries. In this paper, cationic cyclopropenium based cross-linked polymer was firstly prepared with the one pot method, and then the counter ion was replaced by TFSI− anion using simple ion replacement. Cationic cyclopropenium hyper-crosslinked polymer (HP) was introduced into a polyethylene oxide (PEO) matrix with the solution casting method to prepare a composite polymer electrolyte membrane. By adding HP@TFSI to the PEO-based electrolyte, the mechanical and electrochemical properties of the solid-state lithium-sulfur batteries were significantly improved. The PEO-20%HP@TFSI electrolyte shows the highest Li+ ionic conductivity at 60 °C (4.0 × 10−4 S·cm−1) and the highest mechanical strength. In the PEO matrix, uniform distribution of HP@TFSI inhibits crystallization and weakens the interaction between each PEO chain. Compared with pure PEO/LiTFSI electrolyte, the PEO-20%HP@TFSI electrolyte shows lower interface resistance and higher interface stability with lithium anode. The lithium sulfur battery based on the PEO-20%HP@TFSI electrolyte shows excellent electrochemical performance, high Coulombic efficiency and high cycle stability. After 500 cycles, the capacity of the lithium-sulfur battery based on PEO-20%HP@TFSI electrolytes keeps approximately 410 mAh·g−1 at 1 C, the Coulomb efficiency is close to 100%, and the cycle capacity decay rate is 0.082%.

Highlights

Hebei Key Laboratory of Functional Polymers, Department of Polymer Materials and Engineering, School of Science, Nantong University, Nantong 226019, Jiangsu, China
The preparation sketch of cyclopropenium cationic-based hyper-crosslinked polymer (HP) is shown in Figure 1a, and the related SN2 mechanism is shown in Scheme S1
In the FT-IR spectrum of HP@Cl (Figure S1), the stretching vibration peak of the C-Cl bond in pentachlorocyclopropane at 635 cm−1 disappeared, and a signal at 1545 cm−1 corresponding to the tensile vibration peak of the aromatic cyclopropenium ring was observed, which proves that the cationic-based HP were successfully obtained

Summary

Introduction

By adding HP@TFSI to the PEO-based electrolyte, the mechanical and electrochemical properties of the solid-state lithium-sulfur batteries were significantly improved. The lithium sulfur battery based on the PEO-20%HP@TFSI electrolyte shows excellent electrochemical performance, high Coulombic efficiency and high cycle stability. Lithium sulfur (Li-S) batteries have received tremendous attention in recent years due to their high theoretical energy density (2600 Wh·kg−1 ) and large theoretical capacity (1675 mAh·g−1 ) [5,6]. Despite their considerable advantages, the application of

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Conclusion