Hierarchical Nanosheet Arrays of Metal Oxides Guide Uniform Deposition for Lithium Anode

Lithium metal, regarded as the "Holy Grail" of lithium battery anodes, has been considered as the most promising material for high-energy density rechargeable batteries. However, its practical application has been hindered by the uncontrolled dendrite growth of the lithium metal during charge-discharge cycles. Guiding uniform deposition of lithium during cycling is an effective route to solve the problem. In this contribution, nanosheet arrays of lithiophilic metal oxides with a hierarchical structure, that is, primary vertical thin arrays coupled with secondary grid-like ones, were constructed on a Cu current collector to regulate lithium nucleation and growth. It was found that the primary vertical thin nanosheet arrays could reduce the current density and provide adequate lithiophilic sites with a lower nucleation barrier, while the secondary grid-like nanosheet arrays offered facile Li-ion diffusion and a large volume for lithium deposition. Owing to the uniform deposition behavior and stable electrode structure, the modified Li anode showed a high Coulombic efficiency of 98% for 230 cycles. When the structured anode was assembled with a LiFePO4 cathode, the full cell presented markedly enhanced capability retention and improved rate performance.