Kızılaslan Abdulkadir, Kırkbınar Mine, Cetinkaya Tugrul, Akbulut Hatem
Engineering Faculty, Metallurgy and Materials Engineering Department, Sakarya University, 54187 Sakarya, Turkey.
Phys Chem Chem Phys. 2020 Aug 5;22(30):17221-17228. doi: 10.1039/d0cp03442h.
Recently, tailored synthesis of solid electrolytes satisfy multiple challenges, i.e. high ionic conductivity and wide (electro)chemical stability window is of great interest. Although both oxide- and sulfide-based solid electrolytes have distinguished merits for meeting such concerns separately, a new solid electrolyte having the excellent aspects of both materials is pursued. Herein, we report the synthesis of a sulfur-doped Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolyte with a NASICON crystal structure that combines elevated ionic conductivity with intrinsic stability against an ambient atmosphere. Sulfur doping was carried out using sulfur-amine chemistry and the system was characterized by XRD, Raman, XPS, ICP-OES, and EDS analyses. Bader charge analysis was carried out with the aid of density functional theory calculations to characterize charge accumulation in the local environment of the bare and sulfur doped LATP structures. Our results indicate that the partial replacement of oxygen with sulfur yields higher ionic conductivity due to the lower electronegativity of sulfur compared to oxygen, which reduces the attraction of lithium ions. The enhanced ionic conductivity of LATP is attributed to a decreased lithium ion diffusion activation energy barrier upon sulfur doping. Compared to bare LATP, the as-prepared sulfur doped LATP powders were shown to decrease the activation energy barrier by 10.1%. Moreover, an ionic conductivity of 5.21 × 10-4 S cm-1 was obtained for the sulfur doped LATP powders, whereas bare LATP had an ionic conductivity of 1.02 × 10-4 S cm-1 at 40 °C.
最近，定制合成满足多种挑战的固体电解质，即具有高离子电导率和宽（电）化学稳定性窗口，引起了极大的兴趣。尽管基于氧化物和硫化物的固体电解质分别在满足这些问题方面具有显著优点，但人们仍在寻求一种兼具两种材料优异特性的新型固体电解质。在此，我们报道了一种具有NASICON晶体结构的硫掺杂Li1.3Al0.3Ti1.7(PO4)3（LATP）固体电解质的合成，该电解质结合了提高的离子电导率和对环境气氛的固有稳定性。使用硫胺化学进行硫掺杂，并通过XRD、拉曼、XPS、ICP-OES和EDS分析对该体系进行表征。借助密度泛函理论计算进行巴德电荷分析，以表征裸露和硫掺杂LATP结构局部环境中的电荷积累。我们的结果表明，用硫部分替代氧会产生更高的离子电导率，这是因为硫的电负性低于氧，从而降低了锂离子的吸引力。LATP离子电导率的提高归因于硫掺杂后锂离子扩散活化能垒的降低。与裸露的LATP相比，所制备的硫掺杂LATP粉末的活化能垒降低了10.1%。此外，硫掺杂LATP粉末在40℃时的离子电导率为5.21×10−4 S cm−1，而裸露的LATP在该温度下的离子电导率为1.02×10−4 S cm−1。
