Laser Sintering of Solid Electrolyte for the Next Generation Battery

Summary:

Inorganic solid electrolytes enable the next generation battery with enhanced safety, increased volumetric energy density and expanded operating temperature range in comparison to their liquid counterparts. However, after the reagent’s synthesis a densification process, the sintering, follows which describes a heat treatment with high temperatures and enduring dwell times. In general, sintering densifies the samples and reduces loose grains, enlarges grains and minimises the grain resistance. Furthermore, samples with high density imply a low porosity and a high ionic conductivity, a case desired in all-solid-state batteries.
There are various methods to generate these properties, such as conventional sintering with a constant heating rate in a furnace or the field-assisted sintering technology (FAST). In the last-mentioned method, a high current is introduced directly to the pressing tool to heat the mould, which contains the ceramic powder. As a result, this technique achieves very high heating rates and short dwell time due to the effective heat generation, which allows a flexible production of small to medium quantities. Nevertheless, this method also has several disadvantages. For instance, only simple geometric forms are possible due to the mould shape and extreme tool wear when sintering hard ceramics. Moreover, the addition of graphite to isolate the powder from the tool forces is an additional purification step to remove undesirable contaminants.
Therefore, this study evaluates laser sintering as a technique for ceramic all-solid-state batteries. This approach eliminates the depicted disadvantages of current sintering methods and benefits from the laser’s flexibility and rapid processing time. However, the sinterability of LATP as an inorganic solid electrolyte is evaluated by varying relevant parameters e.g. velocity. The effect on surface temperature is discussed.