Regulating Key Variables and Visualizing Lithium Dendrite Growth: An Operando X-ray Study

Abstract

Although Li metal has long been considered to be the ideal anode material for Li rechargeable batteries, our limited understanding of the complex mechanism of Li plating has hindered the widespread deployment of Li metal anodes. Therefore, operando studies are required to unambiguously reveal the complex mechanistic steps involved. In this study, we employed synchrotron-based X-ray imaging methods to visualize the evolution of Li plating/stripping under operando and, more importantly, practical conditions for battery operation, providing detailed insights into morphology evolution during Li plating. The effects of critical battery operating parameters, including concentration of Li salts, current density, ionic strength, and various electrolytes and additives, on Li plating/stripping have been studied. The delicate interplay of these conditions on the resulting Li metal morphology has been characterized for the first time.

In situ observation of solid electrolyte interphase evolution in a lithium metal battery

“…2 shows a high magnification of some of the isles that are surrounded by high numbers of dendrites in the hollow region. This phenomenon was also reported by Yu et al 20 . Figure 3b, c show three isles in another region of the anode after 9 and 14 days of cycling, respectively.…”

“…Figure 3a shows a higher magnification of one of the isles, where we see that two dendrites with needle morphology have formed. The wall of the isle contains fresh lithium metal from the interior of the anode that has not been in contact with the rest of the battery, which is more prone to dendrite formation 20 . Supplementary Fig.…”

“…After that, further decomposition of the salt may result in the formation of Li 2 S, LiC x F y , LiF, Li x CNF 3 , and Li y SO x surrounding the isle. The LiF surrounding the isle acts as a SEI layer to protect the lithium in the isle from further dissolving, as Li ion transfer in LiF is slower than that of Li 2 CO 3 and Li 2 O 20,24 . Salt decomposition was also reported by Chao et al 25 using Xray photoelectron spectroscopy (XPS), where a more severe The cycling points at which these images were obtained are indicated in Supplementary Fig.…”

Atomic‐Scale Visualization of Electrochemical Lithiation Processes in Monolayer MoS2 by Cryogenic Electron Microscopy

“…Recently, as battery-operated portable devices and hybrid/electric vehicles have become more widespread, energy storage demands have increased. [1][2][3][4][5] Up to now, lithium ion batteries (LIBs) have been the dominant energy storage device due to their high energy and power densities, and long lifespan. [6][7][8][9] However, increases in the energy density of LIBs have not kept pace with the increasing energy demands, so development of new, high capacity electrode materials is urgently required.…”

Diffusion Limitation of Lithium Metal and Li–Mg Alloy Anodes on LLZO Type Solid Electrolytes as a Function of Temperature and Pressure

“…[1][2][3][4] While in LIBs with liquid electrolytes, lithium dendrite growth and low Coulombic efficiency prevent the use of lithium metal as an anode material, [3,[5][6][7][8][9][10][11] solid electrolytes (SEs) had been predicted to be able to block dendrite growth due to their high shear modulus. [1][2][3][4] While in LIBs with liquid electrolytes, lithium dendrite growth and low Coulombic efficiency prevent the use of lithium metal as an anode material, [3,[5][6][7][8][9][10][11] solid electrolytes (SEs) had been predicted to be able to block dendrite growth due to their high shear modulus.…”