VACUUM CARBON TECHNOLOGIES
Corrosion of Al foil
The foil was dried in a vacuum oven at 120°C for 6 h and then transferred to a glove box. Coin cells of Li/electrolyte/Al in which electrolyte and separator were sandwiched between two electrodes were assembled. The separator was Celgard 2400 that was wetted by the liquid electrolyte (commercial LP30 lithium-ion battery electrolyte). Lithium metal and Al foil were punched into a 16 mm diameter disk as an electrode. The electrochemical measurements were performed using an VMP3 model potentiostat. Linear sweep voltammetry (LSV) measurements were performed from 2 to 5 V at 1 mV/s sweep rate.
It was found that the anodic current increased abruptly at about 3.2 V versus Li during the anodic scan of unprotected Al foil, which implied that the dissolution of aluminum occurred on the Al anode surface. It was found that the anodic current increased at above 4.2-4.3 V versus Li during the anodic scan of carbon protected Al foils (samples 1525 and 1528). Besides, the anodic current for carbon protected Al foils was much smaller than that for unprotected Al foil. Thus, Al with carbon layer is stable anodically in the lithium-ion batteries electrolytes due to the presence of protective carbon layer.