Highly Stable Quasi-Solid-State Anode-Free Lithium Metal Batteries Enabled by Dynamic Integrated Interface Engineering

Anode-free lithium metal batteries offer unprecedented energy density and simplified manufacturing processes, emerging as a transformative platform for sustainable energy storage systems. However, their practical implementation is hindered by low lithium plating/stripping reversibility. Herein, we propose dynamic integrated interface engineering strategy involving the incorporation of a minimal Ag-based multifunctional initiator (AMI) into the electrolyte, and leveraging its controlled-release function to simultaneously achieve Cu current collector modification, SEI reconstruction, and in-situ electrolyte polymerization after battery assembly, thereby enabling efficient long-term cycling of anode-free lithium metal batteries in a unified process. AMI is composed of silver cations and anions with strong Lewis acid properties. Firstly, by adjusting the plating potential, the Ag + provided by AMI can be reduced to silver particles and achieve precise morphology control. This significantly enhanced the lithium affinity of the Cu foil. Additionally, the in-situ polymerization induced by anions of AMI facilitates electrolyte-electrode connections, ensuring a robust charge transfer for Li + . Importantly, through the synergistic interactions of interfacial metal modification and AMI anions-induced ring-opening polymerization of solvents (1,3-Dioxolane, DOL), the adsorption capacity of the current collector for anions and the solvation sheath in electrolytes can be both altered, enabling in-situ formation of a bilayer-inverted SEI architecture with a unique organic-rich inner layer and inorganic-rich outer layer (OI-IO) structure on the electrode surface. This OI-IO structure, sustained by the substrate-anchored anionic groups, effectively maintains a high content of inorganic components in the outer SEI layer during repeated cycling, thereby constructing a sturdy and long-lasting protective barrier. Consequently, the anode-free Cu||LiFePO 4 (LFP) full cell demonstrates 90% capacity retention over 200 cycles, while high-loading cathodes (>12 mg cm -2 ) under lithium-limited conditions (N/P=0.8) maintain stable operation for 300 cycles. In addition, at an N/P ratio of 1 and a charge/discharge rate of 0.5 C, the capacity retention rate remains above 90% after 1100 cycles. The assembled Cu||LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) pouch cell achieves a capacity of up to 2.25 Ah and an energy density of nearly 467 Wh kg -1 .