Laser-Induced Silicon Oxide for Anode-Free Lithium Metal Batteries

Abstract

The development of a rechargeable Li metal anode (LMA) is an important milestone for improved battery technology. Practical issues hindering LMAs are the formation of Li dendrites and inactive Li during plating and stripping processes, which can cause short circuits, thermal runaway, and low coulombic efficiency (CE). Here, the use of a laser-induced silicon oxide (LI-SiO_x ) layer derived from a commercial adhesive tape to improve the reversibility of Li metal batteries (LMBs) is studied. The silicone-based adhesive of the tape is converted by a commercial infrared laser into a homogeneous porous SiO_x layer deposited directly over the current collector. The coating results in superior performance by suppressing the formation of Li dendrites and inactive Li and presenting higher average CE of 99.3% (2.0 mAh cm^-2 at 2.0 mA cm^-2 ) compared to bare electrodes. The thickness and morphology of the deposited Li is investigated, revealing a different mechanism of Li deposition on coated electrodes. The laser coating affords a method that is fast and avoids the use of toxic organic solvents and extensive drying times. The improved performance with the SiO_x coating is demonstrated in LMB with a zero-excess ("anode-free") configuration where a 100% improved performance is verified.

Keywords: Li metal batteries; anode-free batteries; laser coating method; laser-induced silicon oxide.