Selection of Lithium Chip, Separator and Electrolyte for Coin Cell Lab Research

Lithium Chip

Metal lithium chip used in the laboratory can provide a far greater source of lithium, Lithium chip shall have less impurities and the size shall be larger than that of the electrode to be measured, and the purity of lithium chip shall not be less than 99.9%. General requirements for lithium chip in the preparation of coin cell: diameter 15 ~ 15.8mm (the corresponding electrode size is 14mm for CR2032  button cell), thickness 0.5 ~ 0.8mm, surface straight, silver white light, no oil spots, no perforation or tear.

Battery Separator

The type of battery separator should be selected according to the experimental requirements, Generally, the insulation film with nanometer pores is selected, which can allow bidirectional ion transport after adsorption of electrolyte, single or multilayer polyethylene or polypropylene membranes are often used. The battery separator was prepared into a regular round shape by a punching machine, the size should be larger than the lithium metal chip and the electrode to be measured to isolate the cathode and anode electrode sheets, usually the same as the inner diameter of the coin cell case (For example, the diameter of the separator used for CR2032 is 15.5 ~ 16.5 mm). Celgard2400 or Celgard2500 industrial polypropylene film is often used in laboratory.

Electrolyte

LiPF6 system electrolyte is usually used to assemble button lithium ion batteries for laboratory use (For example, the electrolyte of LFP battery is generally LiPF6 solution with the concentration of 1 mol/L, and the mixture of EC/DEC is 1∶1 (volume ratio) as the solvent), and can be selected according to the experimental requirements, such as the selection of common ratio electrolyte, electrolyte containing one or more additives. The amount of electrolyte used in coin cell assembly is usually excessive, for example, the amount of electrolyte used in button cell CR2032 is generally 100 ~ 150μL, the amount of electrolyte used in simulated cell is generally 200μL. If a long cycle test is required, the amount of electrolyte can be appropriately increased.