Impact of in coin cell atmosphere on lithium metal battery performance

Research on lithium metal as a high-capacity anode for future lithium metal batteries (LMBs) is currently at an all-time high. To date, the different influences of a highly pure argon glovebox (GB) and an industry-relevant ambient dry room (DR) atmosphere have received little attention in the scientific community. In this paper, we report on the impact of in coin cell atmosphere (ICCA) on the performance of an LMB as well as its interphase characteristics and properties in combination with three organic carbonate-based electrolytes with and without two well-known interphase-forming additives, namely fluoroethylene carbonate (FEC) and vinylene carbonate (VC). The results obtained from this carefully executed systematic study show a substantial impact of the ICCA on solid electrolyte interphase (SEI) resistance (RSEI) and lithium stripping/plating homogeneity. In a transition metal cathode (NMC811) containing LMBs, a DR ICCA results in an up to 50% increase in lifetime due to the improved chemical composition of the cathode electrolyte interphase (CEI). Furthermore, different impacts on electrode characteristics and cell performance were observed depending on the utilized functional additive. Since this study focuses on a largely overlooked influential factor of LMB performance, it highlights the importance of comparability and transparency in published research and the importance of taking differences between research and industrial environments into consideration in the aim of establishing and commercializing LMB cell components.