Lightweight Shield to Stabilize Li Metal Anodes at High Current Rates

Lithium metal batteries (LMBs) are considered one of the most attractive high-specific energy storage devices. However, their popularization and application are plagued by the uncontrollable lithium deposition and unlimited volume expansion of lithium metal anodes during the repeated depositing/stripping. Here, we load a metal-organic framework (ZIF-67) on a three-dimensional (3D) flexible melamine sponge (MS) through a liquid phase reaction to prepare a MS with ZIF-67 nanoparticles (MSZ). The unique MSZ interlayer can offer accommodation space for "hostless"lithium; the specific pore structure and polar chemical structure of the MS/ZIF-67 work together to guide uniform lithium deposition. The Li-Cu cells with the MSZ interlayer exhibit remarkable electrochemical performance with a small voltage hysteresis less than 105 mV beyond 250 cycles (5 mA cm-2), and the high Coulombic efficiency remains over 98% after 700 cycles at 1 mA cm-2. Even at an extremely high current density of 10 mA cm-2, this enhancement is achieved. The introduction of the MSZ interlayer into Li/LiFePO4 cells enhances their cycling performance with a reversible specific capacity of 99.7 mAh g-1 over 1000 cycles at 1C. Our work provides new ideas for stable high-specific energy lithium metal batteries.