Lithium metal batteries (LMBs) with high energy densities are regarded as the most promising candidates for next-generation energy storage. However, the practical applications of LMBs have long been limited by the uncontrollable lithium (Li) dendrite growth resulting from the unstable solid electrolyte interphase (SEI). We herein proposed an in situ regulated SEI that is rationally designed by the introduction of a functional separator. In details, a lignosulfonate film with intrinsic reactivity toward Li metal is integrated onto the surface of a routine separator. The as-regulated SEI possesses favorable inorganic-rich species and inherited aromatic groups, synergistically endowing rapid ion transport capability and superior mechanical stability. Consequently, the in-situ stabilization of the electrode/electrolyte interfaces contributes to a reduced voltage polarization and a remarkably prolonged cycle life of the working LMBs, which intrinsically indicates a more uniform Li electroplating manner with well-suppressed dendrite formation. This work highlights a facile yet highly efficient strategy of designing stable SEI through reactive separator and affords fresh insights into the interface regulation for Li anode protection in practical LMBs.

具有高能量密度的锂金属电池（LMB）被认为是下一代储能的最有希望的候选者。但是，LMB的实际应用长期以来一直受到不稳定的固体电解质相（SEI）导致的不可控制的锂（Li）枝晶生长的限制。我们在此提出了一种通过引入功能性分离器进行合理设计的原位调节SEI。详细地，具有对Li金属的固有反应性的木质素磺酸盐膜被集成到常规隔板的表面上。规定的SEI具有良好的富含无机物的种类和继承的芳族基团，协同赋予了快速的离子传输能力和优异的机械稳定性。所以，电极/电解质界面的原位稳定有助于降低电压极化并显着延长工作LMB的循环寿命，这从本质上表明了一种均匀的Li电镀方式，并充分抑制了枝晶的形成。这项工作强调了一种通过反应性隔板设计稳定SEI的简便而高效的策略，并且为实际LMB中锂阳极保护的界面调节提供了新的见解。