Morphological and Chemical Mapping of Columnar Lithium Metal

Abstract

The development of high energy density lithium metal batteries requires the successful implementation of thin lithium metal anodes with limited excess lithium. Primary electrodeposition is a strategy for on-site production of thin lithium metal and avoids the costs and challenges of traditional lithium metal foil processing and transport. Herein we explore the interfacial parameters governing deposition of up to 30 μm uniform columnar lithium in LiF-rich environments, by investigating the effects of both the substrate/lithium and electrolyte/lithium interfaces for three common electrolytes: carbonate, fluorinated carbonate, and ether-based. By analyzing the transition to growth heterogeneity at higher current densities and later stage deposition, we confirm that improved growth uniformity is coupled with increasingly stable solid electrolyte interphases, but that this correlation differs for the three electrolytes. In comparison with conventional dimethyl carbonate, fluorinated carbonate and ether-based electrolytes exhibit fewer chemical shifts in the morphological transition region. We pinpoint the chemical origins of growth transitions in conventional dimethyl carbonate and show that close-packed columnar growth can be electrodeposited in ether-based electrolyte at 100-fold higher current densities.

The roles of nucleation and growth kinetics in determining Li metal morphology for Li metal batteries: columnar versus spherical growth

“…4 For these reasons, recent efforts have been devoted to suppressing Li dendrite formation [5][6][7][8] and deciphering the plating and stripping mechanism of Li metal. [9][10][11][12][13][14][15] However, the electroplating mechanism of Li metal was not fully claried; thus Li metal morphology was still uncontrollable during electroplating.…”

Mapping Techniques for the Design of Lithium‐Sulfur Batteries

“…As observed in XPS spectra, charge-discharge process leads to the phase decomposition of Li/LPS into Li 2 S, Li The relationship between Li deposition and electrolyte/Li interfaces was investigated via optical/SEM images and XPS mappings. [54] Three different electrolyte methods were applied: carbonate-based (1 m LiPF 6 in dimethyl carbonate, DMC), fluorinated carbonate (1 m LiPF 6 DMC + 10% fluoroethylene carbonate, FEC), ether-based (1 m LiTFSI in 1,3-dioxolane:1,2dimethoxyethane, DOL:DME, v% = 1:1). Fluorinated carbonate, and ether-based electrolytes will form more stable SEIs without the growth of ramified Li dendrite.…”

“…F 1s and O 1s XPS mapping and the corresponding line scans for columnar Li deposition in 1 m LiPF 6 DMC at a) 0.5, b) 2, c) 4 mA cm −2 ,respectively. Reproduced with permission [54]. Copyright 2020, American Chemical Society.…”

Nonreactive Electrolyte Additives for Stable Lithium Metal Anodes

“…The dendrite-free morphology for Li deposition is homogeneous, densely packed with low specific surface area, thus minimizing side reactions and improving the cycle life of LMBs. 48,49 Following the above-mentioned strategies, researchers have achieved great results which are summarized in Table 1.…”