Overcoming Copper Substrate Thermodynamic Limitations in Anode-Free Lithium Pouch Cells via In Situ Seed Implantation

Anode-free lithium metal batteries (AFLMBs) exhibit enhanced energy density and cost-effective manufacturing, albeit constrained by short lifespans due to inhomogeneous lithium nucleation and growth on the inherently lithiophobic Cu current collector. Although numerous attempts at Cu surface modifications aim to mitigate this thermodynamic limitation, they often result in substantial irreversible capacity loss and/or lack the stability required for practical applications. Here, we present an in situ seed implantation (ISI) strategy to address the aforementioned challenge. A 36 s ISI treatment created an ultrathin lithium metal layer, composed of uniform lithium nuclei with ∼100 nm in diameter, equating to 0.05 mAh cm^-2, on the Cu substrate. This approach facilitates dense lithium deposition during cycles, effectively doubling the lifespan of an Ah-level 437 Wh kg^-1 AFLMB. Our ISI strategy offers a straightforward and efficient solution that maintains battery energy density and manufacturing cost effectiveness, and its application extends beyond lithium metal.