Application Notes - Magnetic Resonance

Li₁₀SnP₂S₁₂: An Affordable Lithium Superionic Conductor

State-of-the-art lithium-ion batteries utilize liquid electrolytes consisting of LiPF₆ dissolved in flammable alkyl carbonates.

State-of-the-art lithium-ion batteries utilize liquid electrolytes consisting of LiPF6 dissolved in flammable alkyl carbonates. These electrolytes exhibit a high ionic conductivity around 10 mS/cm at room temperature and a lithium transference number of ∼0.35. However, safety concerns are a major issue. Overheating and overcharging of the battery may lead to a decomposition of the solid electrolyte interface (SEI) and to chemical reactions between electrolyte and electrode materials. The resulting temperature increase may then cause melting of the separator and finally burning of the battery. Therefore, it would be preferable to use exclusively nonvolatile and nonflammable battery materials, especially in the case of high-energy batteries for the automotive sector.

The superionic conductor shown in this paper Li10SnP2S12 was investigated by PFG NMR using gradients up to 12 T/m. This was achieved by using a Diff50 dedicated diffusion probe driven by a GREAT60 gradient current amplifier. The diffusion results can be used to relate the material transport to the observed conductivity.

More details are given in the publication: Bron P, Johansson S, Zick K, Schmedt auf der Günne J, Dehnen S, Roling B. Li10SnP2S12: an affordable lithium superionic conductor. J Am Chem Soc. 2013;135(42):15694-15697. doi:10.1021/ja407393y

Stimulated echo intensity as a function of the squared gradient amplitude from a 7Li pulsed field gradient NMR experiment. A diffusion coefficient of 1.8 × 10−12 m2/s is obtained according to the equation Aecho(g2) = A exp[−Dγ2δ2(Δ−δ/3)g2].