Application of dry high-energy ball-milling to increase the density and grain boundary conductivity of solid ceramic electrolytes: Li_1.3Al_0.3Ti_1.7(PO₄)₃ as a case study

In this work, the effect of high energy ball milling (HEBM) on the density and conductive properties of as-prepared Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) solid ceramic electrolyte has been demonstrated. It has been shown that the composition of the LATP phase remains unchanged after HEBM. A gradual decrease in the average crystallite size was observed during the HEBM duration. The multimodal particle size distribution in HEBM samples has a positive effect on their densification during pressing, allowing the use of low pressure (~ 5 MPa). High-density LATP ceramics (~ 89% of the theoretical value) with an ionic conductivity of 2.15∙10⁻⁴ S∙cm⁻¹ were obtained after 30 min of HEBM. The value of electronic conductivity obtained by the analysis of DC polarization using blocking Ag electrodes is equal to 8.3∙10⁻⁹ S∙cm⁻¹. The HEBM approach is accessible and easy to implement. This method does not require high pressure, long sintering temperature and/or time, and additional reagents such as fusible additives. The use of HEBM allows the density and ionic conductivity of the resulting ceramics to be adjusted.