Fast-Charging and Ultrahigh-Capacity Lithium Metal Anode Enabled by Surface Alloying
Tianhui Xu,1 Peng Gao,1 Peirong Li,1 Kai Xia,1 Na Han,1 Jun Deng,1 Yanguang Li,*,1 and Jun Lu*,2
1Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Soochow University Suzhou 215123, China
2 Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL 60439, USA.
Li metal anodes are going through a great revival but they still encounter grand challenges. One often neglected issue is that most reported Li metal anodes are only cyclable under relatively low current density (<5 mA cm-2) and small areal capacity (<5 mAh cm-2), which essentially limits their highpower applications and results in ineffective Li utilization (<1%). Herein, it is reported that surface alloyed Li metal anodes can enable reversible cycling with ultrafast rate and ultralarge areal capacity. Low-cost Si wafers are used and are chemically etched down to 20-30 µm membranes. Simply laminating a Si membrane onto Li foil results in the formation of LixSi alloy film fused onto Li metal with mechanical robustness and high Li-ion conductivity. Symmetric cell measurements show that the surface alloyed Li anode has excellent cycling stability, even under high current density up to 25 mA cm-2 and unprecedented areal capacity up to 100 mAh cm-2. Furthermore, the surface alloyed Li anode is paired with amorphous MoS3 cathode and achieves remarkable full-cell performance.