Highly Reversible Lithium Metal Anode Enabled by 3D Lithiophilic-Lithiophobic Dual-Skeletons.

Lithium metal is a promising anode for high-energy-density lithium batteries, but its practical application is still hindered by intrinsic defects such as infinite volume expansion and uncontrollable dendrite growth. Herein, a dendrite-free 3D composite Li anode (Li-B@SSM) is prepared by mechanical rolling of lithiophilic LiB nanofibers supported by Li-B composite and lithiophobic stainless-steel mesh (SSM). Featuring hierarchical lithiophilic-lithiophobic dual-skeletons, the Li-B@SSM anode shows an ultrahigh Coulombic efficiency of 99.95% and a long lifespan of 900 h under 2 mA cm /1 mAh cm . It is demonstrated that the abnormally reversible Li stripping/plating processes should be closely related to the site-selective plating behavior and spatial confinement effect induced by the robust lithiophilic-lithiophobic dual-skeletons, which alleviates the volume changes, suppresses the growth of Li dendrites, and reduces the accumulation of "dead" Li. More importantly, the application feasibility of the Li-B@SSM anode is also confirmed in full batteries, of which the Li-B@SSM|LiFePO full cell shows a high capacity retention of 97.5% after 400 cycles while the Li-B@SSM|S pouch battery exhibits good cycle stability even under practically harsh conditions. This work paves the way for the facile and efficient fabrication of high-efficiency Li metal anodes toward practical applications.