Guiding bottom-up lithium growth with lithium-intercalated graphite in a separator-integrated reduced graphene oxide host for extended lithium metal battery lifespans

초록

Lithium metal batteries (LMBs) have been identified as a potential solution for next-generation energy storage, owing to their high theoretical capacity and low redox potential. Nevertheless, the process of repeated plating/stripping can lead to the formation of dendrites and dead lithium, which poses significant challenges to safety and cycle life. In addressing these challenges, this study proposes a separator-integrated electrode comprising reduced graphene oxide (rGO) and Li+ intercalated graphite, obtained through an alternating current (AC) electrochemical exfoliation method. The mixture of rGO and unexfoliated graphite fragment (WPG@GF) is deposited on a glass fiber (GF) separator using a water-based centrifugation and vacuum filtration process. The presence of unexfoliated graphite promotes Li+ intercalation, creating a lithiophilic layer that facilitates uniform and stable lithium deposition. Electrochemical tests demonstrate a coulombic efficiency of similar to 99% in half cells and a full cell capacity retention of 90% over 200 cycles at 1C with an LFP cathode. This approach paves the way for safer, longer operating LMBs.

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