Doctor-Blade Casting Fabrication of Ultrathin Li Metal Electrode for High-Energy-Density Batteries

摘要

The employment of ultrathin Li metal electrodes with matched capacity with current cathodes and improved electrochemical stripping/plating behaviors plays a key role in the realization of high-energy-density batteries. However, their fabrication remains challenging using regular cold rolling processing due to inferior processibility of metallic Li. Herein, a facile molten metal doctor-blade casting approach is explored to fabricate uniform metallic Li layers with thickness ranging from 10 to 50 mu m on regular battery Cu current collectors with a lithiophilic Sn interphase layer. The enhanced surface wettability between Li and the spontaneously formed Li-Sn alloy helps to realize uniform spreading, and formation of an ultrathin and uniform metallic Li layer. The existence of the Li-Sn alloy in the bulk of metallic Li electrode helps to reduce the nucleation barrier and improve the electrochemical performance of the Li metal. With a cathode areal capacity of 2.8 mA h cm(-2) the LiCoO2||Li/Li-Sn full cell shows improved capacity retention from 58% to 77% after 100 cycles at a lower Negative/Positive ratio of 2/1, offering a high energy density of 662.4 W h kg(-1). The enhanced electrochemical performance of the as-fabricated ultrathin Li metal electrode with high energy density opens up a promising pathway for realizing next-generation high-energy-density batteries.