Regulating\nLithium Electrodeposition with Laser-Structured\nCurrent Collectors for Stable Lithium Metal Batteries

Abstract

Lithium-metal\nbatteries (LMBs) are promising electrochemical energy\nstorage devices with high energy densities. However, the extreme reactivity\nof metallic lithium, the large volumetric change of the electrode\nduring cycling, and the notorious dendrite formation issues lead to\nlow cyclic stability and safety concerns, hindering the practical\napplication of LMBs. In particular, the intrinsic tendency of uneven\nlithium deposition and the large internal electrode stress lead to\nthe piecing of solid electrolyte interphases (SEIs), thereby resulting\nin fast decay of the anode. We develop a facile laser processing technique\nto fabricate laser-structured copper foils (LSCFs) that are able to\nregulate the lithium deposition kinetics and increase the cycle life\nof LMBs. By simply scribing commercial foils using a 355 nm laser,\nmicrostructural features with fish-scale patterns are obtained. The\nlithium deposition follows a drastically different mode on the LSCF\ncompared with commercial planar copper foils which relieves the internal\nstress of lithium and prohibits the piecing of SEI. A high Coulombic\nefficiency of >96% of the lithium metal anode is maintained for\nover\n100 cycles on the LSCF at a current density of 1 mA cm^–2 and an areal capacity of 1 mAh cm^–2 while the\nbenchmark decayed to below 80% after 50 cycles. Full cells based on\nLiFePO₄ cathodes display a reasonable specific capacity\nof 125 mAh g^–1 over 300 cycles at a rate of 1 C.\nThis work provides a fast yet effective laser-based approach to construct\nhighly stable lithium metal anodes.