This report summarizes the results regarding the scale-up activities of materials, electrodes and lithium-ion cells produced at RSE, based on MXene and oxidized MAX phase. The activity included the installation and use of a pilot line for cutting and welding electrodes with 4,5 cm x 5,8 cm size, as well as sealing them in lithium ion pouch cells.

In the initial phase, the synthesis of materials has been scaled up by increasing the quantity of powders in production batches and monitoring the formation of coherent phases using chemical/physical characterization techniques, in particularly X-ray diffraction, similar to those produced in smaller batches for material study, in the order of milligrams.

The next step involved producing electrodes with increasing thickness to determine the electrode mass loading and calculate the capacity value per unit area, as a function of deposition thickness.

Subsequently, pouch cells have been cut and assembled, aiming at matching electrodes with similar capacity/area ratio to impose the cathodic material as capacity limit of, simulating the case of assembling a real battery, and thus preventing electrolyte degradation due to dendrite formation during lithium cell charging. It was found during this phase that, for good electrochemical stability, electrode thickness should not exceed 0,25-0,4mm during slurry deposition.

With these thicknesses, using a mixing technique adapted from conventional chemical laboratory procedures and scaled up with larger quantities of powders compared to those used for material study and validation, it has determined that the optimal capacity per unit area is approximately 0,8-0,9 mAh/cm², ensuring at least 300 charge and discharge cycles.

In addition to cell testing to obtain devices with at least 15-20 mAh, more similar to real devices, the activity also allowed to: i) verify for the first-time the employ of MXene as an anodic material in lithium-ion batteries (in previous years, MXene had only been studied for sodium ion batteries); ii) to validate the electrode pre-lithiation technique used in previous years, but it showed limitations in applicability as device size increased.

The Report is available on the Italian site