Dendrite-free Li metal anode by lowering deposition interface energy with Cu99Zn alloy coating

Abstract

Li should be the ultimate anode due to its highest theoretical capacity and lowest electrochemical potentials. However, the dendrite formation has been the grand challenge hindering their direct use. Here we modified the commercial anode Cu current collectors with atomically distributed Zn artificial defects by magnetic sputtering of Cu₉₉Zn. Zn has definite solubility in Li metal and can form solid solution before Li metal deposition, lowering the deposition interface energy between current collectors and metal anodes. With atomically distributed seeds, significantly improved performance of Li metal anodes was achieved with depressed dendrite formation on both planar and 3D Cu. The Li-Li symmetric cell can be stably cycled for more than 1000 h. Coulombic efficiency over 98% at Li deposition capacity of 10 mAh cm⁻² could be maintained. We anticipate that high performance lithium metal batteries could be realized by using this anode combined with optimized electrolytes and cathodes.