Hi all,
I have question regarding charging and discharging lihium coin cell (CR2032).
My coin cell used LCO/Li as the electrodes, ionic liquid in polymer as the electrolyte.
After assembly in glove box, I let the coin cell rest (OCV) for 24 hours and charge the cell to 4.4 V and discharge the cell to 2.7 V with constant current of 0.01 mA. However, after 3 cycles, my cell has only 0.14-0.17 mAh of discharge capacity. I have problem using higher current, as when higher current (0.1 mA or more) is used, the voltage will instantly spike above 5V and prompt safety alert. I have no idea which part of my procedure went wrong. Hopefully anyone with experience can share their thoughts and views.
There are 2 possible reasons if you are sure there is no problem with LCO.
1. Cell assembly: you may assemble cells in an improper way, therefore, Ohmic resistance is too large.
2. Your electrolyte: maybe only a small amount of Li+ participates in transportation, so the capacity is very low.
Did you check its ionic conductivity and transference number?
An-Giang Nguyen I see, I have not checked the ionic conductivity yet. I am trying to interpret the EIS data that I obtained, not sure how to identify the bulk resistance yet.
This is a cell problem, not a degradation phenomenon.
He set up a proper program with a cut-off potential range of 2.7-4.4V. The cell was charged to 5 V due to the resolution limit of the cycler or the time interval issue. Probably, the cell was charged for a few milliseconds to 5 V which could not be recognized by the cycler. Therefore, the cell did not go to the next step. Then, immediately, the safety alert was notified.
An-Giang Nguyen you are correct. I tried the system with a 3-electrode system setup but with LCO/Li without reference. The 3-electrode system used can be found in the link below. However, with the proper setup, my cell could not charge properly. I always wonder if it is because I place the positive and negative electrodes the wrong way. After assembly, the OCV should be positive, am I right? I put let LCO as the positive and Li as the negative.
https://redox.me/collections/batteries-supercaps/products/three-electrode-battery-test-cell-compression-controlled
Tommy Hoong Wy Lee
The OCV should be positive, probably > 3 V. When you connect it to the channel of cycler, the positive value should be observed.
So if you do all steps correctly andthis phenomenon still occurs, I recommend testing with a conventional liquid electrolyte to find the cause.
- Badges
- Science topic