High-Power Hybrid Solid-State Lithium–Metal Batteries Enabled by Preferred Directional Lithium Growth Mechanism

Abstract

Solid electrolytes are revolutionizing the field of lithium–metal batteries; however, their practical implementation has been impeded by the interfacial instability between lithium metal electrodes and solid electrolytes. While various interlayers have been suggested to address this issue in recent years, long-term stability with repeated lithium deposition/stripping has been challenging to attain. Herein, we successfully operate a high-power lithium–metal battery by inducing the preferred directional lithium growth with a rationally designed interlayer, which employs (i) crystalline-direction-controlled carbon material providing isotropic lithium transports, with (ii) prelithium deposits that guide the lithium nucleation direction toward the current collector. This combination ensures that the morphology of the interlayer is mechanically robust while regulating the preferred lithium growth underneath the interlayer without disrupting the initial interlayer/electrolyte interface, enhancing the durability of the interface. We illustrate how these material/geometric optimizations are conducted from the thermodynamic considerations, and its applicability is demonstrated for the garnet-type Li7–xLa3–aZr2–bO12 (LLZO) solid electrolytes paired with the capacity cathode. It is shown that a lithium–metal cell with the optimized amorphous carbon interlayer with prelithium deposits exhibits outstanding room-temperature cycling performance (99. 6% capacity retention after 250 cycles), delivering 4.0 mAh cm–2 at 2.5 mA cm–2 without significant degradation of the capacity. The successful long-term operation of the hybrid solid-state cell at room temperature (approximately a cumulative deliverable capacity of over 1000 mAh cm–2) is unprecedented and records the highest performance reported for lithium–metal batteries with LLZO electrolytes until date.