Efficient and robust lithium metal electrodes enabled by synergistic surface activation–passivation of copper frameworks

Abstract

The synergistic surface tailoring of three-dimensional Cu frameworks achieved via Ag-induced activation and Al2O3-induced passivation leads to a significant improvement in the Li plating–stripping efficiency and cycling performance.

Bottom-Up Lithium Growth Triggered by Interfacial Activity Gradient on Porous Framework for Lithium-Metal Anode

“…To date, considerable research effort has been devoted to mitigating the dendritic growth of metallic Li. In particular, metallic Li storage in three-dimensional (3D) framework electrodes is considered effective for resolving dendrite-induced problems. − The 3D framework electrodes with large surface areas and high porosities have the ability to confine metallic Li within their porous architectures, which should result in reduced local (effective) current densities and increased tolerance to volume variation . However, they still exhibited uneven Li plating–stripping, which turned out to be more severe than those of planar electrodes, depending on the materials and architectures.…”

“…However, they still exhibited uneven Li plating–stripping, which turned out to be more severe than those of planar electrodes, depending on the materials and architectures. During Li plating, Li preferentially nucleates and grows on top of the framework electrode (top growth) because the ionic resistance of electrolyte-filled pores inhibits the migration of Li + deep into the electrode bottom. ,− In contrast to general expectations, 3D framework electrodes tend to exhibit poor cycling stability and early cell failure under both normal and high-current operations.…”

“…Figure schematically illustrates the Li plating phenomena in 3D framework electrodes. The Li plating process involves the following multiple reactions competing with each other (Figure a): (i) Li + migration toward the bottom in electrolyte-filled pores, (ii) electron conduction toward the top through the framework, and (iii) interfacial charge transfer (Li + reduction) on the framework surface. ,, In general, Li + transport in the electrolyte-filled pores is relatively sluggish, imposing large ionic resistances, whereas electron conduction through the metallic framework is very facile. For the conventional framework with a uniform, reasonable interfacial activity (e.g., 3D-Cu), Li nucleation and subsequent growth preferentially occur on top of the electrode, leaving the inner pores empty (Figure b).…”

Conformal Coating of a Carbon Film on 3D Hosts toward Stable Lithium Anodes

“…18,19 It is known that the growth of Li dendrites can be delayed by reducing the local current density (based on the model of Sand's time). 20 Therefore, there has been renewed interest in 3D scaffold materials, 21,22 including copper foam, 23 nickel foam, 24−26 and carbon frameworks 27−29 to accommodate the volume expansion of Li and inhibit the dendritic growth by extending the time when dendrites begin to grow (Sand's time). 30 In some cases, periodic 3D scaffolds are used to adjust the electric field and guide the lateral deposition of lithium.…”

“…Recently, considerable literature has been reported focusing on the theme of the protection of the lithium metal anode. − Many strategies include the modification of the complanate copper surface to promoting the uniform deposition of lithium through uniform lithium nucleation. − However, the occurrence of Li dendrites cannot be completely avoided during long-term cycling, especially when the batteries are operated at high current densities. , It is known that the growth of Li dendrites can be delayed by reducing the local current density (based on the model of Sand’s time) . Therefore, there has been renewed interest in 3D scaffold materials, , including copper foam, nickel foam, − and carbon frameworks − to accommodate the volume expansion of Li and inhibit the dendritic growth by extending the time when dendrites begin to grow (Sand’s time) . In some cases, periodic 3D scaffolds are used to adjust the electric field and guide the lateral deposition of lithium. , These strategies avoid the vertical growth of Li dendrites toward the separator and the cathode, thus the batteries can still operate properly even if the dendrites substantially increase.…”