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Molecular Dynamics Investigation on Electrolyte Properties ofLithium Ion Battery During Charge and Discharge(PDF)

《南京师大学报（自然科学版）》[ISSN:1001-4616/CN:32-1239/N]

Issue:
2020年02期
Page:
43-48
Research Field:
·化学·
Publishing date:

Info

Title:
Molecular Dynamics Investigation on Electrolyte Properties ofLithium Ion Battery During Charge and Discharge
Author(s):
Liu Man1; Yang Jinfei2
(1.School of Chemistry and Chemical Engineering,Beijing Institute of Technology,Beijing 102488,China)(2.School of Chemistry and Materials Science,Nanjing Normal University,Nanjing 210023,China)
Keywords:
lithium ion batteries electrolyte; electric field; dielectric constant; coordination number; ion pair
PACS:
O645.17
DOI:
10.3969/j.issn.1001-4616.2020.02.008
Abstract:
The model of multi-component mixed electrolyte solvent EC-DMC-DEC(ethylene carbonate-dimethyl carbonate-diethyl carbonate)was established by molecular dynamics simulation for investigating the micro-structure of Li+in the mixed electrolyte. The properties of mixed solvent under zero electric field and electric field were calculated and analyzed. The calculation results show that there is no contact ion pair(CIP)and ion aggregate(AGG)in the electrolyte under 0V electric field. However,CIP exists in electrolyte with different concentration of LiPF6 under 6V electric field,which reduces the solubility of lithium salt. The existence of the electric field makes the dipole moment of the solvent molecule of the electrolyte coincide with the direction of the electric field. The solvent molecules are arranged in order,which lowers the dielectric constant of the solvent,promotes the formation of CIP and AGG and the reduction of the coordination number of lithium ions. Therefore,destroying the order of the solvent molecules under electric field and enhancing the dielectric properties of the solvent are crucial for reducing the ion association and improving the performance of the electrolyte,which serves as a theoretical reference for optimizing LIBs electrolyte properties.

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Last Update: 2020-05-15