The increasing demand for higher density of energy storage requires breakthroughs in secondary battery techniques and systems. Metallic lithium (Li⁰) is attractive because it can be a common anode material for the lithium-sulfur (Li-S), lithium-oxygen (Li-O₂ or Li-air) and all-solid lithium batteries due to its low electrode potential (-3.04 V vs. SHE) and high specific capacity (3860 mA h g^-1) among the known anode materials. However, it is not viable in commercial secondary batteries at present because of its high activity towards the liquid electrolytes, and safety issues associated with the growth and fracture of Li dendrites during cycling. These issues have been obsessing the scientists and hindering the commercialization of secondary lithium batteries for decades.

Herein, controlled deposition of Li metal was realized on specially designed micro-/nano-architectured Si wafer and ZnO nanowires array, on the basis of preferential deposition of Li in the grooves of micro-patterned Ti foil, all showing the confining or guiding effect of the porous structure on Li metal deposition. The preferential deposition (and sometimes the growth) of lithium in the defected grooves of inactive Ti foil, in the micro-wells of active Si, and in the nanopores formed by bunches of active ZnO nanowires, indicate that the Li-storage activity of the material becomes less important in some particular cases but their appropriately designed micro- or nano-architectures become the dominating factor, to determine where the lithium will be deposited. These findings enrich our understanding on the intercalation and deposition properties of lithium and provide important revelations on effectively controlling the intercalation, deposition and growth of lithium, and suppressing the growth of lithium dendrites. The hetero-epitaxial growth of lithium on ZnO nanowires further demonstrates that the crystallographic structure of the electrode material can even affect the growth direction of the lithium nanowires.

We expect that the concept of designing micro-/nano-architectured electrodes be a promising strategy to tackle some of the obsessing issues of the Li metal anode and promote the commercialization of the secondary lithium batteries.

Acknowledgements

This work was financially supported by the National 973 Program of China (No. 2015CB251100).