There is an increasing demand for high-capacity lithium-ion batteries. All-solid-state batteries can use a lithium-metal anode and maximize the energy density. One of the key challenges in this context is the efficient manufacturing of solid electrolytes. Lithium thiophosphates, for example, provide high conductivities and good processability. One example is Li₃PS₄, which is typically prepared from Li₂S and P₄S₁₀. Splitting the adamantane-cage-like precursor P₄S₁₀ has been proposed to be the rate‐limiting reaction step.

Wolfgang Zeier, University of Münster, Germany, and colleagues have developed an approach in which P₄S₁₀ is readily and cleanly split using pyridine. The resulting stable pyridine–P₂S₅ complexes were then used in the solvent-based synthesis of the electrolyte Li₃PS₄. The team mixed P₄S₁₀ powder with pyridine and obtained py₂P₂S₅⋅0.5py after overnight crystallization (reaction pictured). This reactant, together with Li₂S, was then used to synthesize Li₃PS₄ in an acetonitrile solution.

Using this approach, the synthesis time of Li₃PS₄ was significantly reduced—from days to hours. This is due to the increased reactivity of the P₂S₅ complexes. This work has implications for a better understanding of electrolyte synthesis and for developing improved processes.

• Pyridine Complexes as Tailored Precursors for Rapid Synthesis of Thiophosphate Superionic Conductors,
  Michael Ghidiu, Roman Schlem, Wolfgang G. Zeier,
  Batteries Supercaps 2021.
  https://doi.org/10.1002/batt.202000317