Problems of corrosion and other electrochemical side processes in lithium chemical power sources with non-aqueous electrolytes

Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries

“…In a working lithium ion cell that uses liquid electrolytes, the thin coating of active electrode materials is soaked with the liquid electrolytes and the interaction between the electrolyte components and the current collectors strongly affects the performance stability of the cell, especially at the cathode side, where Al is constantly held at high potentials. It has been confirmed by numerous observations that, in well-cycled lithium ion cells, the Al substrate suffers severe pitting-like corrosion at a fully charged state, which leads to a shortened calendar life and fading capacity. ,, Because very thin Al foils are used (down to 10 μm) in consideration of the energy density, the pitting could cause complete disintegration and fragmentation in some cases.…”

“…It has been confirmed by numerous observations that, in well-cycled lithium ion cells, the Al substrate suffers severe pitting-like corrosion at a fully charged state, which leads to a shortened calendar life and fading capacity. 298,318,319 Because very thin Al foils are used (down to 10 µm) in consideration of the energy density, the pitting could cause complete disintegration and fragmentation in some cases. Few significant efforts were made on this issue before a new lithium salt (LiIm) was found to cause serious Al corrosion in nonaqueous electrolytes during the early 1990s.…”

“…141 Microscopic examination of the aged Al retrieved from well-cycled cells found that, even in electrolytes based on LiPF 6 or LiBF 4 , localized pitting occurred on the Al (Figure 26a). 298,318,319 Closer examination of these corrosion sites under an SEM revealed that what had optically appeared to be a "pit" was actually a "mound" or "nodule" (Figure 26b) where both Al(0) and Al 2 O 3 existed, according to XPS analysis. 321 Due to the anodic state of the Al during the electric cyclings in these cells, the presence of Al(0) practically suggests that the mounds were somehow electrically isolated from the foil.…”

Electrochemical behavior of current collectors for lithium batteries in non-aqueous alkyl carbonate solution and surface analysis by ToF-SIMS

“…Passive films are believed to be oxide/hydroxide containing water molecules, especially when formed in aqueous solution. Few examples show electrochemical behavior of those metals in anhydrous solutions [7][8][9][10][11][12][13][14][15][16][17][18]. Thus, little is known about the formed passive films and the formation processes.…”

Effects of Nanowire Length on Charge Transport in Vertically Aligned Gold Nanowire Array Electrodes

“…The energy and power densities of devices are largely dependent on the choice of the current collector, even when the same active materials are used. − In particular, electrodes fabricated with interpenetrating three-dimensional (3D) ion and electron transport pathways have been proven to exhibit charge-transport properties superior to those of their planar counterparts. − These electrodes are prepared through the deposition of the active layer onto suitable current collectors with stereoscopic 3D surface structures (henceforth, “3D current collectors”), such as copper pillar arrays, nickel foams, − stainless steel meshes, , polymer scaffolds, − carbonaceous materials, , and nanoporous gold. − Alternatively, gold-nanowire current collectors can provide superior performance in combination with active materials such as carbon nanotubes and manganese dioxides. , Nevertheless, the charge capacity per unit mass of the active material often decreases with an increase in the loading of the active material. , This adverse effect is most likely related to the increased charge-transport path length on thickening of the active layer. To circumvent this limitation, 3D current collectors should be engineered in such a way as to increase their volumes and surface areas, i.e., the height and roughness factor (RF), so that they can be coated with large amounts of thinner active layers.…”