Constructing Self-Adapting Electrostatic Interface on Lithium Metal Anode for Stable 400 Wh kg~(?1) Pouch Cells

摘要

The realization of large-capacity, high-energy-density Li metal battery technologyis seriously impeded by dendrite growth and massive dead lithiumformation upon cycling. Here, a stable flexible electrostatic self-adaptingpolymer (poly(1-benzyl-3-vinylimidazolium), (PBM)) interface is reported toregulate lithium-ion deposition for dendrite-free lithium metal batteries. Thecationic PBM interlayer can adaptively tune the surface current densitynear the lithium/electrolyte interface, inducing a uniform distribution ofcurrent density and lithium ions and thus achieving dendrite-free Li depositionunder harsh conditions (lean electrolyte 8.75 μL mAh~(?1), high arealcapacity >4 mAh cm~(?2)). Moreover, the tethered phenyl groups endowPBM with a low reduction potential of ?3.7 V versus standard hydrogenelectrode by decreasing Hirshfeld charge at the reductive site. This avoidselectrochemical reduction and therefore ensures the long-term stability of thePBM interface. Consequently, the LiPBM@Cu asymmetric cells deliver a highaverage 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_2PBM@Li pouch cell exhibits excellentcycling 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 capacity5.7 mAh cm~(?2), and high current density 2.7 mA cm~(?2)).