Tuning the Metal Ions of Prussian Blue Analogues in Separators to Enable High-Power Lithium Metal Batteries

The Li dendrite issue is the major barrier that limits the implement of Li metal anode practically, especially at high current density. From the perspective of the nucleation and growth mechanism of the Li dendrite, we rationally develop a novel Prussian blue analogues (PBA)-derived separator, where tuning the metal ions bestows the PBAs with open metal site to confine anion movement and thereby afford a high Li⁺ transference number (0.78), and PBA with ordered micropores could act as an ionic sieve to selectively extract Li⁺ and thereby homogenize Li⁺ flux. This demonstrates a highly reversible Li plating/stripping cycling for 3000 h at a practically high current density (5.0 mA cm^–2). Consequently, a high loading Li||LiFeO₄ battery (∼10.0 mg cm^–2) demonstrates ultralong cycling life at high current densities (∼5.1 mA cm^–2). This work highlights the prospect of optimizing PBAs in regulating ion transport behavior to enable high-power Li metal batteries.