Substrate effects on Li⁺ electrodeposition in Li secondary batteries with a competitive kinetics model

Abstract

A Li22Sn5 alloy was prepared as a novel substrate of the metallic Li anode of rechargeable Li batteries for Li(+) deposition. The performance of this alloy substrate was compared with those of Li, Cu, and Sn substrates. The deposition-stripping cycling performance of Li on the substrates was studied through the galvanostatic charge-discharge method and cyclic voltammetry. The morphologies of the substrates before and after Li(+) deposition were investigated through scanning electron microscopy and digital video microscopy. The electrochemical kinetics of Li(+) electrodeposition on the different substrates was studied through the galvanostatic pulse method and linear sweep voltammetry. The solid electrolyte interface films of Li deposits on the substrates were characterized through electrochemical impedance spectroscopy. Results show that Li22Sn5 is an excellent substrate for metallic Li electrodes. "The competitive kinetics model" was proposed as a novel mechanistic model to explain the electrodeposition behavior of Li(+) on general substrates based on electrochemical kinetic principles.

Accurate Determination of Coulombic Efficiency for Lithium Metal Anodes and Lithium Metal Batteries

“…These microstructures resemble puzzle pieces, indicating preferential growth of Li in certain crystal planes. Although the scope of this study is not to examine the morphology difference of Li deposited on Li and Cu substrates, the difference in the surface structure (of Li deposited on Cu vs Li) does suggest that the nucleation and growth mechanisms of Li deposition vary depending on the substrate . This can potentially affect the Li CE measurements, which is another reason that Method 3 proposed above is more reliable than other approaches on the accurate determination of an average CE value.…”

Reviving Lithium‐Metal Anodes for Next‐Generation High‐Energy Batteries

“…Apart from the complexities, such assembly/disassembly processes may introduce impurities, induce side reactions toward lithium, and destroy the integrity of the anode. Fortunately, lithium‐containing alloys, like Li–Mg,[19b] Li–B, Li–Sn, etc., have been fabricated and enable dendrite‐free morphologies when used in LMBs. The reasons underneath are related to the difference in deposition kinetics over different media, and their 3D nanostructures that effectively confine the lithium depositions.…”

Solid–Solution-Based Metal Alloy Phase for Highly Reversible Lithium Metal Anode

“…The cyclic voltammetry (CV) of Li20Zn shows typical features of an electrochemical corrosion reaction which can be assigned to the metallic Li stripping-plating (Fig. 1e)30 . However, the cathodic and anodic peaks of dealloying and alloying reactions 31 , respectively, can be observed in the Li20Ag.To further understand the role of solid-solution phase in the delithiation-lithiation process of the Li20Ag, we performed in-situ XRD study on a two-electrode cell, which was assembled with a Li20Agfoil as the working electrode and a Li metal foil as both the counter and reference electrodes in an electrolyte composed of 1M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in 1,3-dioxolane (DOL): dimethoxyethane (DME) (1:1 by volume).…”