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Hexagonal boron nitride inducing anionic trapping in polyethylene oxide based solid polymer electrolyte for lithium dendrite inhibition

Abstract

Here we prepare a hexagonal boron nitride (h-BN)–polyethylene oxide composite polymer electrolyte via a convenient casting method, which shows high mechanical strength. Meanwhile, the electrochemical properties (electrochemical window and lithium ion transference number) are enhanced but the ionic conductivity of the h-BN composite electrolyte is decreased after adding h-BN. Density functional theory (DFT) calculation results show that a stronger binding effect is observed between TFSI− and BN, compared to that between Li+ and BN. Molecular dynamics (MD) simulations are also utilized to study the mechanism behind the enhanced Li ion diffusion by h-BN addition. Li+ diffusion in PEO/LiTFSI/BN is lower than that in the PEO/LiTFSI system, but the diffusion of TFSI− exhibits a more significant decline rate in the presence of BN. This indicates that the presence of BN suppresses anion motion and enhances selectivity in Li+ transport. Thus, the PEO/LiTFSI/h-BN composite electrolyte exhibits higher Li ion conductivity but lower anion diffusivity than the PEO/LiTFSI system. Hence the h-BN composite polymer electrolyte in a Li/Li symmetric battery provides a long cycling time of 430 h at 0.2 mA cm−2. A Li metal/LiFePO4 full battery with the PEO/LiTFSI/h-BN composite electrolyte also works more efficiently for long-term cycling (140 cycles) than a filler-free PEO based electrolyte (39 cycles).

Category

Academic article

Language

English

Author(s)

  • Yuhan Li
  • Libo Zhang
  • Zongjie Sun
  • Guoxin Gao
  • Shiyao Lu
  • Min Zhu
  • Yanfeng Zhang
  • Zhiyu Jia
  • Chunhui Xiao
  • Huaitian Bu
  • Kai Xi
  • Shujiang Ding

Affiliation

  • SINTEF Industry / Materials and Nanotechnology
  • University of Cambridge
  • Beijing Institute of Technology
  • Xi'an Jiaotong University

Year

2020

Published in

Journal of Materials Chemistry A

ISSN

2050-7488

Volume

8

Page(s)

9579 - 9589

View this publication at Norwegian Research Information Repository