Micromorphological Studies of Lithium Electrodes in Alkyl Carbonate Solutions Using in Situ Atomic Force Microscopy

Abstract

The morphology of lithium electrodes in a variety of alkyl carbonate solutions was studied using in situ atomic force microscopy (AFM). We made use of a workstation specially built for the study of highly reactive electrochemical systems by AFM and other scanning probe techniques, based on an evacuable, vibration-protected glovebox. The electrolyte solution used was composed of propylene carbonate (PC), mixtures of ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and Li salts from the following list: LiPF6, LiClO4, LiAsF6, LiN(SO2CF3)2, LiN(SO2CF2CF3)2, and LiC(SO2CF3)3. We studied the effect of solution composition, prolonged storage, Li deposition, and dissolution at low and high current densities. The AFM imaging of these systems shows the complicated morphology of the Li electrodes that depend on the solution composition. We were able to clearly follow the nonuniform nature of Li deposition and dissolution in these systems. We were also able to follow by in situ AFM imaging critical events such as the onset of dendrite formation and the breakdown and repair of the surface films on lithium during Li dissolution at high current densities. The basic morphology of Li electrodes in alkyl carbonate solutions and the condition for the reversible behavior of Li electrodes is discussed.

Metal–Air Batteries with High Energy Density: Li–Air versus Zn–Air

“…[ 62 , 63 ] The SEI layer on the lithium electrode cannot properly accommodate the dramatic morphological changes of the lithium metal upon lithium deposition and dissolution due to the non-uniformity of these processes under high current density ( Figure 6 ). [ 64 ] The SEI layer can be easily cracked and broken during lithium deposition and dissolution. This behavior results in a considerable loss of active lithium metal and solution components due to the complex surface reactions and eventually leads to degradation of the lithium electrode.…”

Understanding the Initial Stages of Reversible Mg Deposition and Stripping in Inorganic Nonaqueous Electrolytes

“…For Li the use of metallic anodes especially challenging due to safety reasons. 5 The path to fully functioning and cost-competitive Mgion batteries begins with addressing a few but complex scientific questions, and perhaps the most pressing is to develop a robust understanding of the atomistic mechanism of reversible plating (or deposition) and stripping (or dissolution) of Mg at the anode/electrolyte interface during battery operation. To date, reversible Mg plating with low over-potential and reasonable anodic stability has been achieved in practice with only a specific class of electrolytes, namely organic or inorganic magnesium aluminum chloride salts (magnesium-chloro complexes) dissolved in ethereal solvents [6][7][8][9][10][11] .…”

Surface Layer and Morphology of Lithium Metal Electrodes

“…5 Especially the electrochemical reaction at the lithium-electrolyte interphase is the dominant process to determine the surface morphology. Therefore many analytical studies concerning the characterization of solidelectrolyte interphase (SEI) layer 6 were carried out using various analytical techniques, such as FTIR, [7][8][9][10] XPS, 11-13 AFM [14][15][16][17] and so forth.…”