We report a new design of synergistic Li metal protective layer for high loading NCA (≥5mAh cm −2 )||Li metal full cell in carbonate electrolytes. The protective layer was designed

based on the functional theory (DFT) calculations: three-dimensional silver and carbon composite nanofiber (Ag/CNF) network with high Li affinity and Pt coated polypropylene

separator with low Li affinity for tailoring horizontal Li deposition on the Ag/CNF protective layer. The Li deposition behavior modulated by the protective layer was thoroughly examined

by initial lithium deposition and cycling behaviors of the Li||Li symmetric cell configuration. Cryogenic focused-ion beam (cryo-FIB) cross-sectional images of the cycled Li anodes

clearly demonstrated that the dense lithium deposition enabled by the synergistic protective layer high loading NCA (≥5 mAh cm −2 )||Li metal full cells. Average cycling performance

improvement by employing the protective layer was 76.45% at various cycling conditions. Our work demonstrates that the synergistic protective layer design is a fruitful pathway to

accelerating the commercialization of the high energy density Li metal batteries in the carbonate electrolytes.