Nano‐Cone Structured Lithiophilic Ni Film on Cu Current Collector Facilitates Li+ Ion Diffusion Toward Uniform Lithium Deposition

Abstract The uncontrolled growth of lithium (Li) dendrite during long‐term cycling has hindered the practical application of the Li metal anode in the next generation rechargeable batteries. A variety of nanostructured current collectors is proposed in Li metal anode to reduce local current density and thus mitigate the Li dendrite formation. Here, the Ni nano‐cone@Al (NCA) structure is utilized to guide the uniform metallic Li nucleation and growth, free from the dendrites. This unique nano‐cone structure can facilitate the ion diffusion toward the bottom of the Ni nanostructures to make effective use of the nano‐cone structure. The surface lithiophilicity is revealed from the view of absorption energy and interface lattice mismatch. It is found that Al on nano‐cone Ni surface decreases the elastic strain energy at the interface rather than decreasing the formation energy. The resulting NCA structured substrate possesses small Li nucleation overpotentials (<0.032 V) and good structural stability upon galvanostatic cycling. Superior cycling stability over 2000 h in a Li|Li symmetric cell is realized. Full cell by paring with LiFePO 4 achieves a high coulombic efficiency of 98.1% for over 100 cycles at 0.2 C with a capacity retention of over 97.2%.