Layered Double Hydroxide Quantum Dots for Use in a Bifunctional Separator of Lithium-Sulfur Batteries | JoVE Visualize

Layered Double Hydroxide Quantum Dots for Use in a Bifunctional Separator of Lithium-Sulfur Batteries

Qing Liu^1,2, Xiaotong Han¹, Hyunyoung Park³

¹School of Chemical Engineering, Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology (SAIHST), and SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon 440-746, Republic of Korea.

ACS Applied Materials & Interfaces|April 6, 2021

View abstract on PubMed

Summary

A novel bifunctional separator using cobalt-aluminum-layered double hydroxide quantum dots and nitrogen-doped graphene effectively suppresses lithium polysulfide shuttling and enhances lithium-sulfur battery performance. This advancement offers a promising solution for high-capacity energy storage.

Area of Science:

Materials Science
Electrochemistry
Nanotechnology

Background:

Lithium-sulfur batteries (LSBs) face challenges like the shuttle effect of lithium polysulfides (LiPS) and slow sulfur conversion kinetics.
Functional separators are crucial for mitigating these issues and improving LSB performance.
Nanostructured materials and chemical modifications offer effective strategies for separator enhancement.

Purpose of the Study:

To develop a bifunctional separator for LSBs using cobalt-aluminum-layered double hydroxide quantum dots (LDH-QDs) deposited with nitrogen-doped graphene (NG).
To investigate the ability of LDH-QDs/NG hybrids to capture LiPS and accelerate redox kinetics.
To evaluate the electrochemical performance of LSBs utilizing the modified separator.

Main Methods:

Synthesis of mesoporous LDH-QDs/NG hybrids.
Coating the hybrids onto polypropylene separators (LDH-QDs/NG/PP).
Characterization using X-ray photoelectron spectroscopy, adsorption tests, Li2S nucleation tests, and electrokinetic analyses.
Electrochemical testing of LSB cells with the modified separator.

Main Results:

The LDH-QDs/NG hybrids exhibit abundant active sites (Co2+ and hydroxide groups) for LiPS capture and redox acceleration.
The resulting LDH-QDs/NG/PP separator (∼17 μm thick) shows high ionic conductivity (2.67 mS cm-1).
LSBs with the modified separator achieved a high discharge capacity (1227.48 mAh g-1 at 0.1C) and excellent cycling stability (0.041% decay per cycle over 1200 cycles at 1.0C).

Conclusions:

The developed bifunctional LDH-QDs/NG/PP separator effectively suppresses the shuttle effect and enhances sulfur conversion kinetics in LSBs.
The strong chemical interactions and catalytic activity of the hybrid material are key to improved performance.
This work presents a viable and economical approach for advanced separator design in high-performance lithium-sulfur batteries.