Lithiophilic Li-Zn alloy modified 3D Cu foam for dendrite-free lithium metal anode

Abstract Three-dimensional (3D) materials are the potential promising lithium (Li) metal anode (LMA) substrates for alleviating volume expansion and inhibiting dendrite formation in high energy density battery systems. Herein, we propose a 3D substrate functioned with Li-Zn lithiophilic alloy surface through lithiation of the electrochemically deposited Zn on Cu foam (3D Li-Zn@Cu foam). This substrate can induce uniform Li deposition along the conductive skeleton, effectively reduce the Li nucleation overpotential and suppress Li dendrite formation. As a result, this substrate exhibits an excellent coulombic efficiency (CE) of 97.8% for 260 cycles at 1 mA cm−2, and with dendrite-free morphology at ultrahigh cycling capacity of 10 mAh cm−2. Symmetric cells with Li-deposited Li-Zn@Cu foam (Li@Li-Zn@Cu foam) electrode can be stably operated over twice lifespan than that of Li@Cu foam. Furthermore, full cells paired with LiFePO4 or sulfur cathodes exhibit remarkable discharge capacities and capacity retention. It is well confirmed that the Li-Zn alloy coating method provides a new light on modifying the surface of 3D skeleton materials for dendrite-free LMA.