One of the most revolutionary technologies developed in the past few decades is the Li-ion battery (LIB) which has successfully prevailed in the market of miniaturized electronics and electrical vehicles. The understanding of fundamental solid-state physics and electrochemistry allowed the implementation of LIBs for e-mobility (electric cars, buses, trucks, scooters, bikes…) and grid-scale energy-storage applications. Despite the progress achieved in LIBs manufacture, the exploitation of this technology is now limited by the commercially available electroactive materials. Indeed, those materials give a realistic energy density of less than 250 Wh kg^-1  in the cylinder cells and less than 300 Wh kg^-1 in the pouch cell models[1].

Several options are on the table to improve the energy density of secondary batteries. Lithium Metal Batteries (LMB) stand out among them because they implement a Lithium Metal Anode (LMA) which offers higher gravimetric and volumetric energy density. Nevertheless, LMBs are not free from their own limitation; for instance, the use of metallic Li prompts safety concerns and difficulties for the processing during cell assembly[2].

Therefore, the development of LMBs without metallic Li in the negative electrode when the cell is assembled would be highly desirable from the manufacturing point of view, and very promising from the commercialization and application standpoint. This concept, known as anode-less or anode-free, has attracted increasingly the attention of the battery community lately.

The aim of the AM4BAT project is to develop innovative component materials and to assemble an anode-free all-solid-state battery (ASSB) manufactured by a cost-competitive and sustainable vat photopolymerization 3D printing. The objective is to reach a high-performance battery with an energy density of 400 Wh kg^-1 and 1000 Wh L^-1 for electric vehicles applications. In that sense, the aim of this research is to develop 3D-metallic nanostructured and lithiophilic current collector as anode for ASSBs. This anode-less system will avoid the limitations of graphite or Li metallic as anode (e.g., mechanical degradation, dendrites formation) while providing benefits (e.g., increasing the gravimetric and volumetric energy density, safety, manufacturing cost).

The development of the lithiophilic current collector was carried out in collaboration with MKS Instruments-ATOTECH® which provided the electrolytic baths for electroplating. Two different types of metals (Ag or Sn) were electrochemically deposited on a Cu current collector. Then, they were electrochemically characterized : Stripping plating vs Li metallic and charge-discharge in full cell. The results are promising as the cyclability has been improved by around 50% compared to the target (Cu foil). This improvement is due to the intercalation of Li on the cathode and conversion of Li on the anode.