Sequential and Dendrite-Free Li Plating on Cu Foil Enabled by an Ultrathin Yolk-Shell SiOx/C@C Layer

Lithium metal anodes are considered to be the ultimate candidate for Li-based batteries; however, their development is hindered by uncontrollable Li deposition. Porous hosts and Cu foil with lithiophilic decorations have proven effective in Li dendrite suppression. However, the failure of lithiophilic decorations during cycling causes inaccessible encapsulated voids for Li-deposition. And the almost electrochemically inert feature of host/decoration materials will result in undesirable loss in gravimetric capacity. Herein, an ultrathin layer of stable and electroactive yolk-shell SiOx/C@C with designed differences in lithiophilicity is constructed on Cu foil. The more lithiophilic SiOx/C core over doped C shell induces sequential Li plating from intra-particle voids to inter-particle spaces and then above the modification layer. Such a plating process is reversed during Li stripping. Even after considering the mass of SiOx/C@C modification layer, a high specific capacity of 2818 mAh g(-1) can be achieved. The Li-SiOx/C@C-Cu anode demonstrates a decent cyclability over 500 h under strict conditions in symmetric cells. When paired with a LiFePO4 cathode (10.5 mg cm(-2)), the full cell with a N/P ratio of 2 manifests a high capacity retention of 91.3% over 350 cycles, demonstrating its practical application value in future lithium metal batteries.