Surface State Change of Lithium Metal Anode in Full Cell during Long Term Cycles

Abstract

In order to investigate the surface state change of the lithium metal anode during long term cycles, a laminate-type lithium metal rechargeable battery was fabricated from a lithium foil, a Li 4 Mn 5 O 12 electrode, a polyimide (PI) membrane having a three-dimensionally ordered macroporous structure (3DOM) and a 1 mol dm −3 LiPF 6 ethylene carbonate (EC) solution as an anode, a cathode, a separator and an electrolyte, respectively. After the charge/ discharge cycles, the chemical composition at the surface of the lithium metal anode taken from the laminate cell was investigated by X-ray photoelectron spectroscopy (XPS). Decomposition products of electrolyte, e.g. Licontaining organic compounds, LiF or-PO 4 were accumulated on the lithium metal surface during long-term charge/discharge cycles. The accumulation of the decomposition products causes the increase of the lithium ion transport resistance of the battery, resulting in the inhibition of dissolution and deposition of lithium which is associated with drop of capacity.

Lithium metal deposition/dissolution under uniaxial pressure with high-rigidity layered polyethylene separator

“…Various chemical approaches have been studied to solve this drawback, including the used of mixed-electrolyte salts and -solvents and the addition of organic and inorganic additives. [21][22][23] According to the report by Ding et al, the formation of dendritic crystals can be suppressed by the addition of cations with lower standard reduction potentials than that of lithium ions, such as cesium and rubidium ions. 24 Togasaki et al reported that the cycle performance of lithium plating/stripping reaction was stabilized by the use of LiNO 3 as the electrolyte salt.…”

Electrochemical Properties and Deposition/Dissolution Behavior of Li Metal Negative Electrode in VS₄/Li Battery

“…Similar residues have been observed in previous studies, in which the residues were found to contain inactivated Li comprising both chemically formed Li compound and electrically insulated Li metal. 26,[29][30][31][44][45][46] Thus, the amount of the residues is considered to be the dominant factor in determining the Coulombic efficiency of the Li electrode. This result suggests that the efficiency is lower for EC/PC with a mixture of fibrous and cord-shaped residues and high for EC/PC+VC and EC/PC+ FEC without cord-shaped residues.…”

“…21 A number of factors, such as electrolyte composition, current collector, separator, confined pressure, and applied current, affect the cycle performance of Li metal electrodes. [22][23][24][25][26][27][28][29][30][31][32][33][34] Utilization of Li, which determines the practical capacity of the negative electrode, also exerts a significant influence on the cycle performance. 28,[35][36][37] We previously reported that the use of 30% Li severely degrades the cycle performance of the Li negative electrode, using LiFePO 4 as a stable counter electrode to evaluate the Li electrode.…”

Lithium Metal Negative Electrode for Batteries with High Energy Density: Lithium Utilization and Additives

“…The morphology of deposited/ dissolved lithium and the cycle performance of lithium metal negative electrodes are influenced by a number of factors, such as the electrolyte composition, applied current, current collector, separator, and confined pressure. [7][8][9][10] These factors also differ depending on whether a lithium/lithium symmetric cell or full-cell combined with a positive electrode material is used for evaluations. Although these factors have been investigated in detail, limited information is currently available on the effects of lithium utilization on the cycle performance of the cell.…”