Effects of Li content on stability, electronic and Li-ion diffusion properties of Li3xLa(2/3)-x?(1/3)-2xTiO3 surface br

H Biao and S Bao-Zhen and W Jing-Xuan and S Jing and X Bo, ACTA PHYSICA SINICA, 72, 028201 (2023).

DOI: 10.7498/aps.72.20221808

Li3xLa(2/3)-x dagger(1/3)-2xTiO3(LLTO) is a promising solid-state electrolyte for Li-ion batteries. We study theeffect of Li content on the stability, electronic and Li-ion diffusion properties of LLTO surface based on first-principles and molecular dynamics simulations. We consider both Li-poor and Li-rich LLTO surfaces. Theresults show that La/O/Li-terminated LLTO (001) is the most stable crystal surface. Further, LLTO (001)surface gives better stability when Li content is 0.17, 0.29, and 0.38 for Li-poor phase, while 0.33, 0.40, and 0.45for Li-rich phase . Electronic structure calculations infer that in both Li- poor and Li-rich LLTO(001) surfacesthere occurs the transition from conductor to semiconductor with the increase of Li content. Besides, we findthat Li-ion always keeps a two-dimensional diffusion path for different Li content. As Li content increases from0.17 to 0.38 for Li- poor LLTO (001) surface, Li-ion diffusion coefficient increases gradually and Li-ion diffusionbarrier decreases from 0.58 eV to 0.42 eV. Differently, when Li content increases from 0.33 to 0.45 for Li- richLLTO(001) surface, it does not follow a monotonic trend for diffusion coefficient nor for diffusion barrier of Li-ion. In this case, Li-ion diffusion coefficient is the largest and Li-ion diffusion barrier is the lowest (0.30 eV)when Li content is 0.40. Thus, our study suggests that by varying Li content, the stability, band gap, and Li-ion diffusion performance of LLTO (001) can be changed favorably. These advantages can inhibit the formation of lithium dendrites on the LLTO (001) surface

Return to Publications page