No abstract

A new layered organic–inorganic iodido bismuthate is prepared from an in situ condensation reaction of acetone and dimethylammonium iodide.

For the fabrication of high-energy and high-power all-solidstate batteries (ASSBs), easily synthesizable solid electrolytes are needed, which enable fast ion transport inside the composite cathode as well as good contacts between cathode active material and solid electrolyte particles. Regarding the latter, the size ratio of the particles inside the composite cathode has to be optimized. Here, we use a wet ball milling process for the synthesis of agyrodite-type Li 5.5 PS 4.5 Cl 1.5 solid electrolyte par-ticles and study the influence of milling time on particle size and ionic conductivity. With longer milling time, both the solid electrolyte particle size and the ionic conductivity decrease, which exert an opposing influence on the cathode performance. We show that a milling time of approximately 2 h leads to an optimum cathode performance, as this time is sufficient for a favorable particle size ratio, while a strong drop of the ionic conductivity of Li 5.5 PS 4.5 Cl 1.5 is avoided.

Lithium‐ion battery models often neglect the salt concentration polarization inside the electrolyte‐filled pores of the composite electrodes. However, this concentration polarization causes a significant impedance, in particular in the case of electrolytes with low Li+ transference numbers. Here, we analyze in detail measured and calculated impedance spectra of composite electrodes containing a solvate ionic liquid‐based electrolyte and an ionic liquid‐based electrolyte, respectively, in comparison to a conventional carbonate‐based electrolyte. For calculating spectra, we use a recently published model by Huang and Zhang. We find that the impedance at 10−4 Hz, which is relevant for battery cycling rates around 1 C to 2 C, increases in the order carbonate‐based electrolyte<ionic liquid‐based electrolyte<solvate ionic liquid‐based electrolytes, but exhibits a remarkably weak thickness dependence, when the electrode thickness exceeds 50–100 μm. This suggests that electrodes considerably thicker than the conventional 80 μm can be used in batteries without significantly deteriorating battery power.

Single-step ball milling synthesis of a highly conductive glass ceramic solid electrolyte enables a low-impedance all-solid-state battery.