Dopant effect on Li+ ion transport in NASICON-type solid electrolyte: Insights from molecular dynamics simulations and experiments

B Akkinepally and IN Reddy and TJ Ko and K Yoo and J Shim, CERAMICS INTERNATIONAL, 48, 12142-12151 (2022).

DOI: 10.1016/j.ceramint.2022.01.075

The performance of sodium superionic conductor (NASICON)-type LiZr2(PO4)(3) (LZP) solid electrolytes for Li-ion batteries is dependent on their ion transportation properties. Therefore, to achieve high stability, ionic conductivity, and good compatibility with Li, the LZP solid electrolyte has chosen and doped with Al to improve aforesaid properties. Also, the effect of the dopant on various parameters has been investigated via MD simulations and experimentally. In this study, molecular dynamics (MD) simulations were used to investigate the effect of Al doping on the ion transport properties of Li1+xAlxZr2-x(PO4)(3) (LAZP, x = 0.0-1.0) solid electrolytes. A facile solid-state reaction was used to synthesize both pristine and Al-doped solid electrolytes and to estimate the effect of doping on the ionic conductivity and ion diffusion in LZP. Computational and experimental results provided strong evidence of improved ion conductivity and diffusion in LZP owing to the presence of the Al dopant. Furthermore, the computational results agreed well with the experimental results, thereby validating the computational model. A maximum ionic conductivity of sigma(Li) = 2.77 x 10(-5) S cm(-1) (for x = 0.2) was obtained. Enhanced ionic conductivity was observed with Al dopants owing to the creation of interstitial Li ions through a reduction in grain boundary resistance. However, a further increase in the amount of dopant reduced the ionic conductivity of LZP owing to Li-ion trapping at the most stable and metastable sites around the Al insertions. Doped LZP solid electrolytes are suitable for use in energy storage devices because of their enhanced ionic conductivity compared to that of pristine LZP.

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