Long‐Lifespan 522 Wh kg−1 Lithium Metal Pouch Cell Enabled by Compound Additives Engineering

Abstract Matching high‐voltage cathodes with lithium metal anodes represents the most viable technological approach for developing secondary batteries with ultra‐high energy density exceeding 500 Wh kg −1 . Nevertheless, the instability of electrolyte/electrode interface film and commercial electrolytes with cut‐off voltage above 4.3 V is still a major concern. Herein, we present that excellent cycling stability with an ultra‐high cut‐off voltage of up to 5.0 V can be obtained by using three‐component additives containing fluoroethylene carbonate (FEC), hexadecyl trimethylammonium chloride (CTAC), and tri(pentafluorophenyl)borane (TPFPB). Excellent ionic conductivity, robust interfacial films on both electrodes, and long‐lasting uniform Li + regulation ability can be obtained in the modifying electrolyte. Consequently, using a high plating/stripping capacity of 3 mAh cm −2 under the current density of 1 mA cm −2 , lithium symmetric cells demonstrate stable cycling performance exceeding 800 hours. Meanwhile, the 7.3 Ah‐class LiNi x Co y Mn 1‐x‐y O 2 ( x =0.83, NCM83)|Li pouch cells are assembled, which show a high energy density of 522 Wh kg −1 and present excellent stability over 178 cycles with a high initial coulombic efficiency (CE) of 98.0 %.