BiFeO3 Coupled Polysulfide Trapping in C/S Composite Cathode Material for Li-S Batteries as Large Efficiency and High Rate Performance

Balram Tripathi,Ambesh Dixit,Gerardo Morell,Rajesh K Katiyar,Ram S Katiyar

doi:10.3390/en14248362

Balram Tripathi, Ambesh Dixit + Show 3 more

Open Access

https://doi.org/10.3390/en14248362

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Abstract

We demonstrated the efficient coupling of BiFeO3 (BFO) ferroelectric material within the carbon–sulfur (C-S) composite cathode, where polysulfides are trapped in BFO mesh, reducing the polysulfide shuttle impact, and thus resulting in an improved cyclic performance and an increase in capacity in Li-S batteries. Here, the built-in internal field due to BFO enhances polysulfide trapping. The observation of a difference in the diffusion behavior of polysulfides in BFO-coupled composites suggests more efficient trapping in BFO-modified C-S electrodes compared to pristine C-S composite cathodes. The X-ray diffraction results of BFO–C-S composite cathodes show an orthorhombic structure, while Raman spectra substantiate efficient coupling of BFO in C-S composites, in agreement with SEM images, showing the interconnected network of submicron-size sulfur composites. Two plateaus were observed at 1.75 V and 2.1 V in the charge/discharge characteristics of BFO–C-S composite cathodes. The observed capacity of ~1600 mAh g−1 in a 1.5–2.5 V operating window for BFO30-C10-S60 composite cathodes, and the high cyclic stability substantiate the superior performance of the designed cathode materials due to the efficient reduction in the polysulfide shuttle effect in these composite cathodes.

Highlights

The SEM (JEOL 6480LV) system is used for collecting the surface topography of synthesized BFO–C-S composite cathode materials
The X-ray diffraction (XRD) spectra for synthesized BFO–C–S composite cathode materials are shown in Figure 2a for different BFO weight fractions and compared to their respective pristine components, sulfur, and BFO
We have examined and validated the efficient coupling of BFO in C/S composite cathode materials, where polysulfides can be trapped in the cathode because of the internal electric field of ferroelectric BFO particles

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The usage of Li-S batteries results in various issues being encountered, such as fast capacity reduction, less use of active material, short lifespan, and poor Columbic efficiency because of sulfur’s insulating nature and the polysulfide shuttle effect, as well as large fluctuations during charge/discharge cycles [2]. Even with the nanostructuring of cathode materials, there are still challenges in in Li-S batteries, especially the dissolution of lithium polysulfides (Li2Sn, 4 < n < 8) during. LixSy clusters, and electric domain provides intrinsic internal field, trapping heteropolar This approach and enhancing the electrochemical performance of Li-S batteries. Materials have attracted much attention because of the intrinsic polarization field, which may assist in capturing polysulfides, reducing the shuttling tion field, which may assist in capturing polysulfides, reducing the shuttling impact impact on electrochemical performance. Hanced specific capacity and stability of the investigated cathode material

Synthesis of BFO Nanoparticles

Synthesis of BFO–S-C Composite Cathode

Material Characterization and Electrochemical Measurements

X-ray Diffraction and Raman Spectra

Electrochemical Performance

Conclusions