N,N-Dimethylacrylamide-mediated composite artificial solid electrolyte interphase for long-cycling lithium metal batteries

The severe interfacial reaction between the lithium metal anode and the ester-based electrolyte hinders the application of lithium metal batteries. While lithium nitrate (LiNO3) can stabilize the electrode–electrolyte interface, its poor solubility in ester-based electrolytes limits its effectiveness. To address this, we develop a polymerized N,N-dimethylacrylamide (PDMAA)-mediated organic–inorganic composite artificial solid electrolyte interphase (SEI) formed via thermal polymerization of a precursor containing N,N-dimethylacrylamide (DMAA) and LiNO3. DMAA not only exhibits a high donor capacity, facilitating high-concentration LiNO3 dissolution, but also strongly coordinates with H2O molecules, effectively reducing the generation of aggressive hydrofluoric acid (HF) in the electrolyte. The abundant LiNO3 effectively contributes to stable, ion-conductive interphases on both the cathode and the anode. The artificial SEI, through synergistic organic–inorganic interactions, enables uniform lithium deposition, stabilizes the cathode structure, and suppresses the electrolyte hydrolysis. As a result, the symmetric cell achieves stable cycling for over 600 h with a low overpotential (∼34 mV), and the full cell maintains 81.6% capacity after 500 cycles. The cell also exhibits excellent rate-performance attributed to the enhanced interfacial kinetics and moisture-resistance capability due to the scavenging effect of water by PDMAA. This artificial SEI design strategy extends the applicability of LiNO3 in ester-based electrolytes for high-performance lithium metal batteries.