The project “PräLi – Pre‑lithiation of electrodes” ran from 1 October 2019 to 31 March 2023 and was funded under the German Federal Ministry of Education and Research with the grant number 13XP0238A. The consortium comprised Forschungszentrum Jülich GmbH, the Helmholtz Institute Münster (HIMS), and Prof. Dr. Egbert Figgemeier’s group. The partners divided responsibilities so that electrode formulation and pre‑lithiation chemistry were developed at HIMS, while Jülich supplied the pilot‑scale roll‑to‑roll pre‑lithiation line and performed full‑cell testing. The project’s objectives were to increase the specific energy density and cycle life of silicon‑containing anodes by compensating irreversible lithium loss through a controlled pre‑lithiation step.

The technical results demonstrate that a 30 % pre‑lithiation degree yields a >14 % rise in specific energy density relative to a reference cell based on the coating weight, and a 6 % improvement versus a graphite cell. The baseline reference cell, an NCM 622 || Si/graphite design with 20 % SiOx, showed a 7 % energy‑density increase when pre‑lithiated. In addition, the creation of a lithium reservoir during pre‑lithiation improves the coulombic efficiency of silicon‑rich anodes. For the first 100 cycles, the capacity retention of the pre‑lithiated cell matched that of a graphite cell, and the overall cycle life was extended by a factor of more than three compared with the reference. Full‑cell measurements revealed a potential difference of approximately 2.22 V for the pre‑lithiated anode versus 0.19 V for the reference, indicating a substantial increase in usable voltage. The initial capacity boost observed in the full‑cell tests was sustained over many cycles when an additive solution containing 2.0 g L⁻¹ CO₂ and 2.5 wt % each of FEC and TEOSCN was applied during the rinsing step, which also improved the coulombic efficiency.

The roll‑to‑roll pre‑lithiation process proved scalable, enabling continuous production of pre‑lithiated anode material. The project’s findings were incorporated into two patents that protect the pre‑lithiation method and the additive formulation, positioning Forschungszentrum Jülich as a key player in battery manufacturing technology. The success of the pre‑lithiation approach attracted a follow‑up project (KontElAb – FKZ 03XP0460) that will further industrialise the process.

Throughout the project, the partners leveraged each other’s infrastructure to accelerate development. Laboratory screening of pre‑lithiation chemistries was followed by pilot‑scale validation, avoiding the need to develop new standard test methods from scratch. Continuous evaluation and adjustment of the experimental plan ensured efficient use of the allocated funds, although the COVID‑19 pandemic limited some travel and service visits. The collaborative framework, clear role allocation, and shared resources were instrumental in achieving the technical milestones and securing the subsequent funding for industrial implementation.