Constructing Self‐Adapting Electrostatic Interface on Lithium Metal Anode for Stable 400 Wh kg−1 Pouch Cells

Abstract The realization of large‐capacity, high‐energy‐density Li metal battery technology is seriously impeded by dendrite growth and massive dead lithium formation upon cycling. Here, a stable flexible electrostatic self‐adapting polymer (poly(1‐benzyl‐3‐vinylimidazolium), (PBM)) interface is reported to regulate lithium‐ion deposition for dendrite‐free lithium metal batteries. The cationic PBM interlayer can adaptively tune the surface current density near the lithium/electrolyte interface, inducing a uniform distribution of current density and lithium ions and thus achieving dendrite‐free Li deposition under harsh conditions (lean electrolyte 8.75 µL mAh −1 , high areal capacity >4 mAh cm −2 ). Moreover, the tethered phenyl groups endow PBM with a low reduction potential of −3.7 V versus standard hydrogen electrode by decreasing Hirshfeld charge at the reductive site. This avoids electrochemical reduction and therefore ensures the long‐term stability of the PBM interface. Consequently, the Li|PBM@Cu asymmetric cells deliver a high average Coulombic efficiency of 99.38% at 8 mAh cm −2 with lean electrolyte. Notably, the 5.1 Ah LiNi 0.8 Co 0.1 Mn 0.1 O 2 |PBM@Li pouch cell exhibits excellent cycling stability (0.011% decay/cycle) and high energy density (418.7 Wh kg −1 ) under realistic conditions (lean electrolyte 2.5 g Ah −1 , high areal capacity 5.7 mAh cm −2 , and high current density 2.7 mA cm −2 ).