Guided Li deposition by surface micro-patterning of Li metal electrode

Abstract

Uncontrolled Li deposition of Li metal electrode have hampered the evolution of Li metal electrode-based next generation lithium batteries. In this work, we report a guided Li deposition with cubic micro-patterns carved on Li metal electrode surface. The micro-patterned Li (MP-Li) electrodes with two different dimensions (6 and $40\mu m$) are fabricated by a stamping method. Li deposition is preferentially initiated on the top edge for the smaller cavity and the bottom side for the larger cavity. The guided Li depositions lead to significantly enhanced cycling stability due to the more uniform utilization of the Li metal electrodes. The guiding effect is more pronounced for the larger pattern, because the large Li deformation during the pattern formation leads to a large contrast in the SEI resistance between top surface and cavity surface. The Li/LFP cell with the MP-Li electrode shows the longer cycling stability and lower over-potential compared with un-patterned control, demonstrating that the guided Li deposition induced by surface pattern can provide an effective academic strategy for high performance Li metal batteries.