Lithiophilic Magnetic Host Facilitates Target-Deposited Lithium for Practical Lithium-Metal Batteries.

Lithium-metal shows promising prospects in constructing various high-energy-density lithium-metal batteries (LMBs) while long-lasting tricky issues including the uncontrolled dendritic lithium growth and infinite lithium volume expansion seriously impede the application of LMBs. In this work, it is originally found that a unique lithiophilic magnetic host matrix (Co 3 O 4 -CCNFs) can simultaneously eliminate the uncontrolled dendritic lithium growth and huge lithium volume expansion that commonly occur in typical LMBs. The magnetic Co 3 O 4 nanocrystals which inherently embed on the host matrix act as nucleation sites and can also induce micromagnetic field and facilitate a targeted and ordered lithium deposition behavior thus, eliminating the formation of dendritic Li. Meanwhile, the conductive host can effectively homogenize the current distribution and Li-ion flux, thus, further relieving the volume expansion during cycling. Benefiting from this, the featured electrodes demonstrate ultra-high coulombic efficiency of 99.1% under 1 mA cm -2 and 1 mAh cm -2 . Symmetric cell under limited Li (10 mAh cm -2 ) inspiringly delivers ultralong cycle life of 1600 h (under 2 mA cm -2 , 1 mAh cm -2 ). Moreover, LiFePO 4 ||Co 3 O 4 -CCNFs@Li full-cell under practical condition of limited negative/positive capacity ratio (2.3:1) can deliver remarkably improved cycling stability (with 86.6% capacity retention over 440 cycles).