CoO@PAN core-sell structure composite as protective layer for stabilizing lithium metal batteries

The lithium metal anode has been considered the “holy grail” of lithium batteries, but its safety and stability have been compromised by the formation of unstable dendrites. In this study, a CoO@PAN composite with a core-shell structure was prepared via a simple calcination method and used as a protective layer on the surface of lithium metal tablets. The treated lithium tablets exhibited improved electrochemical properties and cycle stability. Symmetric batteries with the CoO@PAN protective layer demonstrated better cycle stability and showed a 300-hour cycle life, compared to only 100 h for pristine lithium tablets. Ex-situ morphology characterization confirmed that the CoO@PAN protective layer could passivate the electrode surface and mediate smooth Li deposition. Galvanostatic intermittent titration technique (GITT) and activation energy (Ea) tests revealed that the CoO@PAN layer had an improved Li + /Li transformation kinetics, which reduced the formation of dead lithium and dendrites. In LiFePO 4 full batteries, the capacity retention of treated lithium tablets increased by 35% after 1000 cycles of consistent operation at a 10 C ultrahigh rate. These results suggest that this effective strategy offers a new perspective on the design of novel protective layers for the next generation of lithium metal batteries.