A Highly Reversible Lithium Metal Anode by Constructing Lithiophilic Bi-Nanosheets

As a favorable candidate for the next-generation anode materials, metallic lithium is faced with two crucial problems: uncontrollable lithium plating/stripping process and huge volume expansion during cycling. Herein, a 3D lithiophilic skeleton modified with nanoscale Bi sheets (Ni@Bi Foam, i.e., NBF) through one-step facile substitution reaction is constructed. Benefiting from the nanoscale modification, smooth and dense lithiophilic Li₃ Bi layer is in situ formed, which improves the uniform deposition of Li subsequently. Meanwhile, the 3D structure inhibits the growth of Li dendrites effectively by reducing local areal current density. Consequently, the NBF exhibits outstanding cycling stability with a high average Coulombic efficiency of 98.46% at 1 mA cm^-2 with 1 mAh cm^-2 (>500 cycles). Symmetrical cell with NBF exhibits a high reversibility at 1 mA cm^-2 with 1 mAh cm^-2 (>2000 h). Moreover, superior long-term cycling and rate performance of NBF@Li anode are also acquired when assembled with high areal loading of LiFePO₄ (10.1 mg cm^-2 ) cathode (Negative/Positive ratio: 2.91). Even in anode-free metal lithium batteries, NBF has higher capacity during cycling compared with NF. To conclude, NBF shows excellent electrochemical performance and provides an idea of facile preparation method which can be extend to other metal batteries.