Ultrathin Al foils to fabricate dendrite-free Li–Al anodes†
Current research has made great progress on lithium dendrite issues by electrolyte and/or electrode engineering, but such modifications usually cause severe capacity loss due to the introduction of extra species in the cells. Herein, ultrathin aluminum foil has been employed to in situ fabricate a Li–Al alloy onto lithium metal as a protection layer. The nanoscale foil has an average thickness of only ∼160 nm and an areal mass of 0.3 mg cm−2. The composite anodes with such a protection layer exhibit significant improvement in cycling stability either in symmetrical cells or in full cells by effectively regulating the lithium plating and alloying behaviors to avoid dendritic morphologies at high plating currents and capacities. Different characterization techniques confirm uniform lithium deposition onto the Li–Al alloy surface. Meanwhile, the protection layer also serves as a buffer to alleviate volume variation during cycling. The straightforward integration of ultrathin low-cost metal foil into a lithium anode is a very competitive strategy for the practical development of lithium metal batteries.