ScholarWorks@성균관대학교

초록

Iron fluoride (FeF3)-based cathodes paired with lithium (Li) metal anodes offer a promising chemistry for highenergy, cost-effective batteries. However, degradations driven by each electrode's instability as well as their crosstalk have plagued their development. Herein, we study the behavior of a co-doped version, Fe0.9Co0.1OF (FCOF), in four compositionally distinct electrolytes under a demanding calendar life test protocol: 45 degrees C for one month. Our results revealed that stabilizing both cathode and anode electrolyte interphases (CEI and SEI) is essential for mitigating both reversible and irreversible losses. We found that a robust CEI can suppress Fe3+ reduction and dissolution, while a stabilized SEI on the Li metal minimizes Fe re-deposition and promotes uniform Li plating. An ideal electrolyte is then tasked to address both interfaces simultaneously. In this regard, we identified a localized high-concentration electrolyte (LHCE) that exhibited favorable interfacial compatibility, mitigating crosstalk-induced degradation. FCOF delivered a discharge capacity of 497 mAh g-1 and demonstrated excellent calendar-life resilience, with less than 5.8% energy loss after one month at 45 degrees C. These results highlight the importance of electrolyte-driven dual interfacial stabilization as a key strategy for realizing the practical viability of high-energy FeF3-Li metal batteries.

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