The Inducement and Rejuvenation of Li Dendrites by Space Confinement and Positive Fe/Co-Sites

The high reactivity of Li metal and the inhomogeneous Li deposition leads to the formation of Li dendrites and dead Li, which impedes the performance of Li metal batteries (LMBs) with high energy density. The regulating and guiding the Li dendrite nucleation is a desirable tactic to realize concentrated distribution of Li dendrites instead of completely inhibiting dendrite formation. Here, a Fe-Co-based Prussian blue analog with hollow and open framework (H-PBA) is employed to modify the commercial polypropylene separator (PP@H-PBA). This functional PP@H-PBA can guide the lithium dendrite growth to form uniform lithium deposition and activate the inactive Li. In details, the H-PBA with macroporous structure and open framework can induce the growth of lithium dendrites via space confinement, while the positive Fe/Co-sites lowered by polar cyanide (-CN) of PBA can reactivate the inactive Li. Thus, the Li|PP@H-PBA|Li symmetric cells exhibit long-term stability at 1 mA cm(-2) for 1 mAh cm(-2) over 500 h. And the Li-S batteries with PP@H-PBA deliver favorable cycling performance at 500 mA g(-1) for 200 cycles.

Automated summary

By modifying the commercial polypropylene separator with a hollow and open framework Fe-Co-based Prussian blue analog (H-PBA), the growth of lithium dendrites can be guided to form uniform lithium deposition and activate the inactive Li, which improves the performance of Li metal batteries.