Hexagonal boron nitride induces anion trapping in a polyethylene oxide based solid polymer electrolyte for lithium dendrite inhibition. Issue 19 (5th May 2020)

• Record Type: Journal Article
• Authors: Li, Yuhan; Zhang, Libo; Sun, Zongjie; Gao, Guoxin; Lu, Shiyao; Zhu, Min; Zhang, Yanfeng; Jia, Zhiyu; Xiao, Chunhui; Bu, Huaitian; Xi, Kai; Ding, Shujiang
• Is Part Of: Journal of materials chemistry. Volume 8:Issue 19(2020)
• Page Start: 9579
• Page End: 9589
• Publication Date: 2020-05-05
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0ta03677c
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Lithium ion conductivity and mechanical strength of a PEO based composite solid polymer electrolyte are improved by adding h-BN. 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).