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Synthesis of Ionic Liquid Based Electrolytes, Assembly of Li-ion Batteries, and Measurements of Performance at High Temperature
Published on: December 20, 2016
Li+ ionic conductivities and diffusion mechanisms in Li-based imides and lithium amide
Wen Li1, Guotao Wu, Zhitao Xiong
1Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023, PR China.
Physical Chemistry Chemical Physics : PCCP
|December 17, 2011
Summary
Lithium ion conductivity was investigated in lithium imides and amide. Li(2)NH exhibits superionic conductivity, while Li(2)Ca(NH)(2) shows moderate conductivity, attributed to diffusion mechanisms and defect properties.
Area of Science:
- Solid-state chemistry
- Materials science
- Computational materials science
Background:
- Lithium-based imides and amides are potential solid electrolytes for advanced energy storage.
- Understanding Li(+) ion diffusion is crucial for developing high-performance lithium-ion batteries.
Purpose of the Study:
- To investigate Li(+) ionic diffusion in Li(2)NH, Li(2)Mg(NH)(2), Li(2)Ca(NH)(2), and LiNH(2).
- To correlate experimental ionic conductivity with first-principles simulation results.
Main Methods:
- Experimental ionic conductivity measurements at room temperature.
- First-principles density functional theory (DFT) simulations.
- Analysis of diffusion pathways and defect formation energies.
Main Results:
- Li(2)NH demonstrated superionic conductivity (2.54 × 10(-4) S cm(-1)).
- Li(2)Ca(NH)(2) showed moderate ionic conductivity (6.40 × 10(-6) S cm(-1)).
- Li(+) ion diffusion in Li(2)NH is likely mediated by defects via octahedral and tetrahedral sites; Li defects are difficult to form in LiNH(2).
Conclusions:
- Experimental and theoretical findings for Li(2)NH are consistent, supporting Frenkel pair or vacancy-mediated diffusion.
- Poor Li(+) ion conduction in LiNH(2) is due to high defect formation energy.
- Li(2)NH and Li(2)Ca(NH)(2) show promise as solid electrolytes.
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