Confined Lithium Deposition Triggered by an Integrated Gradient Scaffold for a Lithium-Metal Anode.

ABSTRACT

Constructing a composite lithium anode with a rational structure has been considered as an effective approach to regulate and relieve the tough problems of a sparkling Li anode. However, the potential short circuits risk that Li deposition at the surface of the framework has not yet been resolved. Here, we present a simple regulating-deposition strategy to guide the preferentially bottom-up deposition/growth of Li. The triple-gradient structure of modified porous copper with electrical passivation (top) and chemical activation (bottom) shows significant improvements in the morphological stability and electrochemical performance. Meanwhile, the in situ generation of Li2Se can as an advanced artificial SEI layer be devoted to homogeneous Li plating/stripping. As a result, the composite anode exhibits a long-term cycling over 250 cycles with a high average CE of 98.2% at 1 mA cm-2. Furthermore, a capacity retention of 94.4% in full cells can be achieved when pairing with LiFePO4 as the cathode. These results ensure a bright direction for developing high-performance Li metal anodes.