Superlithiophilic, Ultrastable, and Ionic‐Conductive Interface Enabled Long Lifespan All‐Solid‐State Lithium‐Metal Batteries under High Mass Loading

Abstract

AbstractGarnet‐type Li6.4La3Zr1.4Ta0.6O12 (LLZTO) suffers from instability against moist air, poor interfacial contact with anode, and serious dendrite issue, which greatly impede its practical application in all‐solid‐state lithium batteries (ASSLBs). Herein, a superlithiophilic, moisture‐resistant, and robust interlayer is demonstrated to overcome these obstacles by in situ forming an AlF3 interlayer on the LLZTO surface. Thanks to the unique property, the AlF3‐modified LLZTO offers a significantly reduced interfacial resistance by more than two orders of magnitude (from 527.5 Ω cm2 for the pristine Li/LLZTO to 1.3 Ω cm2 for the surface‐engineered interface), achieves a critical current density of 1.2 mA cm−2 and long‐term stability of over 4000–4700 h, and endows regulated Li plating/stripping behaviors. Specifically, ASSLBs coupled with LiFePO4 and LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes can stably charge/discharge over 400 and 100 cycles at 0.5 and 0.2 C at 25 °C, with retentions of >80.0% and Coulombic efficiencies of >99.9%, respectively. Particularly, the NCM811‐based full ASSLB with large mass loading of 8.3 mg cm−2 also delivers a discharge‐specific capacity as high as 199.1 mAh g−1 with good rate capability, even approaching to the liquid cells. This study demonstrates a practical solution to address the interfacial challenges and paves the way for practical progress of ASSLBs.