Cooperative stabilization by highly efficient nanoseeds and reinforced interphase toward practical Li metal batteries

Abstract

The practical implementation of Li metal has been severely obstructed by the uncontrolled dendritic Li growth and poor cycling efficiency. Herein, highly lithiophilic, ultrathin (∼60 nm) and conformal bismuth-oxygen-carbon layer-modified carbon fibers (CF@BOC) first prepared from the bismuth-based MOF membrane self-assembly were rationally adopted to stabilize Li metal. Highly efficient ultrasmall (∼1.8 nm) bismuth seeds and in-situ generated Li2O-enriched interphase can cooperatively enable the homogeneous Li nucleation/growth and extraordinarily high Li utilization efficiency. Consequently, the modified Li metal exhibits ultrahigh rate capability (10 mA cm−2) and ultralong lifespan stability (6900 cycles). Impressively, the Li|LiFePO4 full cell delivers an exceptional long-term cycling over 200 cycles under the rather harsh condition of low negative-to-positive-capacity (N/P) ratio (∼0.44) and electrolyte-to-capacity (E/C) ratio (5 g Ah−1). And the Li|LiCoO2 full cell also reveals a prolonged cycling performance even at the ultralow N/P ratio (∼0.26) with a remarkable energy density of 361.3 Wh kg−1. Furthermore, the pouch cell with a high loading cathode (3.6 mAh cm−2) still demonstrates prolonged cycling lifespan under the practical condition of extremely limited Li metal and lean electrolyte. This work enlightens a significant stride toward highly stable Li metal anode for practicability.