Flaky and Dense Lithium Deposition Enabled by a Nanoporous Copper Surface Layer on Lithium Metal Anode

Abstract

Dendritic Li growth is a detrimental killer that threatens the safe operation and wide application of rechargeable Li-metal batteries (LMBs). Tuning the nucleation and growth behavior of Li plating process is, therefore, essential to tackle the dendrite growth problem. Here, we demonstrate a flaky and dense Li growth behavior simply by creating a nanoporous Cu layer on the surface of Li metal anode. Highresolution SEM and AFM measurements reveal that the Li deposits first nucleate as nanoflakes within the pores of Cu layer, then these flakes continuously grow thicker until they fuse together and eventually evolve into an ultra-smooth and dense Li layer. Such a unique Li growth behavior is derived from the nanoporous Cu surface layer, which triggers a synergistic regulation of the electrodeposition kinetics by providing a uniformly distributed electric field, sufficiently enhanced Li + diffusion flux, and also appropriately regulated lithium nucleation kinetics. As a result, stable cycling of the Li|Li symmetric cell and Li metal full cells (Li|LTO/LFP/NCM) can be achieved under high current densities and high deposition capacities. These findings illustrate the feasibility to tailor the Li deposition microstructure, which help to create a highly reversible, nondendritic, and safer Li metal anode for LMB applications.

Reversible Deposition of Lithium Particles Enabled by Ultraconformal and Stretchable Graphene Film for Lithium Metal Batteries

“…Coulombic efficiency (CE), short cycle life, large overpotential, and volume expansion. [8][9][10] Therefore, the non-deformable SEI fails to provide real-time protection for the Li metal during repeated nonplanar morphology change, which is the fundamental cause of Li dendrites and Li pulverization and limits the commercial application of Li metal batteries.…”

“…[11][12] Second, SEI should have uniform morphology and evenly distributed chemical composition. [10] Third, the originally non-uniform Li-ion flux from the electrolyte should be redistributed. [13][14][15] Modifying the in situ formed SEI by electrolyte engineering and building artificial SEI by structure and/or component design are the main approaches to tailor electrochemical properties of the SEI.…”

“…[ 6–7 ] Repeated growth and dissolution of the Li dendrites consume electrolyte and Li metal, forming abundant Li + compounds in the SEI and electrical isolated unreactive metallic Li (as shown in Figure 1a), which results in low Coulombic efficiency (CE), short cycle life, large overpotential, and volume expansion. [ 8–10 ] Therefore, the non‐deformable SEI fails to provide real‐time protection for the Li metal during repeated non‐planar morphology change, which is the fundamental cause of Li dendrites and Li pulverization and limits the commercial application of Li metal batteries.…”

Porous Lithiophilic Li–Si Alloy‐Type Interfacial Framework via Self‐Discharge Mechanism for Stable Lithium Metal Anode with Superior Rate

“…[ 21 ] It is worth highlighting that the thickness and weight of the u‐Si used for LSIF synthesis are much lower than those of metallic Li foil (750 µm, ≈39.87 mg cm –2 ), indicating a negligible effect of introducing the LSIF on the energy density of practical LMB. [ 9,22 ]…”

“…The replete Li deposition onto bare Li after 10 mA h cm –2 (DOC 100%, at a current density of 1 mA cm –2 ) induced a mossy and thick dendritic layer (thickness ≈ 146 µm, the top of Figure 4 e) on the Li surface, consisting of numerous entangled Li dendrites (the bottom of Figure 4e,g). Owing to the intense local current density stemming from the intensified electric field (Figure S10a, Supporting Information), [ 22 ] the Li deposited unevenly on the bare Li, building island‐like sparse domains. After full Li stripping, the Li surface foamed and had an uneven surface (Figure S10b, Supporting Information) [ 47 ] due to the endless dendrite proliferation of the hostless Li (Figure S11, Supporting Information).…”