Simplified Pouch Cell Method for 3-Electrode Re-Testing of Harvested Double-Sided Electrodes From Commercial Lithium-Ion Batteries

Abstract

A pouch cell method for retesting double-sided electrodes harvested from commercial lithium-ion batteries in a 3-electrode cell arrangement has been developed. By relying on pressure from restraint plates to make tab electrical connections, this method (1) requires no welding, (2) does not require a dry room, (3) does not require precision sealing equipment inside of an inert-gas glove box, and (4) does not require removal of composite material off of one side of the electrode which may compromise the composite to be tested on the other side. Lithium chips pressed onto copper mesh serve as the reference and counter electrodes and the electrolyte used was 1.0 M LiPF6 1:1 ethylene carbonate (EC):Diethyl carbonate (DEC) v/v. Electrochemical cycling of electrodes from a commercial 3.6 Ah 18650 lithium-ion cell demonstrated cell function and showed stable capacity and potential charge/discharge profiles after two cycles for the cathode and four cycles for the anode. The areal capacity of the anode and cathode was determined to be 5.50 ± 0.31 and 5.50 ± 0.30 mAh/cm2, respectively, based on a potential range of 0.005–1.5 V versus Li/Li+ for the anode and 3.0–4.25 V versus Li/Li+ for the cathode. High frequency, 500 kHz impedance measurements of the anode and cathode cells shows a real impedance of 1.55 Ohms and 2.17 Ohms, respectively, which is similar to prior studies on pouch cells with continuous tabs of similar capacity.