“Anode-free” lithium metal batteries are among the most promising next-generation energy storage technologies owing to high specific energy and expected operational safety. Despite significant research progress in recent years, applicable key challenges remain to be solved. Inhomogeneous and irreversible lithium metal deposition as well as consumption of electrolyte components upon cell operation yield continuous interfacial changes and losses of available lithium reservoir. [1,2] A common approach to achieving higher reversibility of lithium inventory and improved cell performance involves incorporating alloying interlayers that impart favorable properties, including sufficient ionic conductivity, “lithiophilicity” and more uniform Li-ion flux. The latter may counteract capacity fading due to losses of lithium reservoir while reducing the occurrence of lithium metal deposits with a high surface area. In addition, systematic design of alloying and/or polymer-based artificial interlayers and electrolytes may enhance cycling reversibility of cells, thereby boosting the long-term performance of lithium metal batteries.
In this work, the origins of capacity losses and morphology of lithium deposits in “anode-free” lithium metal cells are evaluated invoking solid-state 7Li NMR protocols.[3,4] Different alloys and artificial coatings are employed as interlayer on copper electrodes to assess the origins of irreversible capacity losses and fractions of ‘dead’ lithium species that impair application of “anode-free” lithium metal batteries. This approach also provides insights into solid electrolyte interphase (SEI) formation. The combined study may afford unprecedented pathways for more tailored designs of electrolytes or artificial interlayers facilitating long-term performance of next-generation “anode-free” lithium metal batteries.[5]

References:
[1] Lennartz, P. et al., Joule 2023, 7, 1471
[2] Brunklaus, G. et al, Nature Reviews Electrical Engineering 2024, 1, 79
[3] Thienenkamp, J. H. et al., Cell Reports Physical Science 2024, 5, 102340
[4] Hsieh, Y.-C. et al., Cell Reports Physical Science 2020, 1, 100139
[5] Krude, A. et al., Manuscript in preparation 2026