Enhancing Li Kinetics Via Selective Repulsion-Adsorption and Intermolecular Ion-Conduction Layers for High-Energy-Density Anode-Free Lithium-Metal Batteries.

Anode-free lithium-metal batteries, offer high energy density, but suffer from limited lifespan due to sluggish Li desolvation at the anode. Conventional artificial layers on the anode attract Li by polar groups, yet inadvertently accumulate solvent molecules near these polar layers, impede desolvation, and form an organic-rich solid electrolyte interphase (SEI) with low ionic conductivity. Herein, a selective repulsion-adsorption strategy is proposed, achieved using a layer (MS layer, 35 nm) comprising polystyrene sulfonic acid (PSS) and montmorillonite (MMT). During electrospray fabrication, the PSS self-assemble, with non-polar benzene rings and C-H main chains facing outward, while the -SO groups are buried underneath. The non-polar components can repel polar solvent molecules, and negatively charged MMT will absorb Li, suppressing solvent accumulation and facilitating desolvation. Meanwhile, the anions attracted by MMT will form an inorganic-rich SEI with superior ionic conductivity. Furthermore, the PSS-MMT interface forms a rapid Li transport pathway with reduced migration barriers. Consequently, anode-free MS-Cu||LFP cells operate over 350 cycles, increasing ≈200% compared with Cu||LFP cells. Additionally, 2 Ah anode-free MS-Cu||LFP (340 Wh kg) and MS-Cu||NCM811 pouch cells (490 Wh kg) maintain 80% capacity after 100 and 50 cycles. This work presents an efficient strategy to enhance Li kinetics for high-performance batteries.