The negative electrode material is made into a negative electrode sheet by mixing, coating, rolling, shooting, and drying.Use a lithium sheet as the positive electrode, assemble it into a button battery for testing, and calculate the gram capacity of the material by testing the capacity of the button battery.

Required materials and equipment;

3.1 Ingredients: first dry the positive electrode material and the conductive agent. First weigh m (about 2.0g) of glue LA133 in grinding, take 2.7m of positive electrode powder and 0.15m of carbon black, stir and mix, add it to grinding, add water and grind for about 30min, according to positive powder: carbon black: glue = 90 : 5:5 ratio to prepare the slurry.

3.2 Coating: Wipe the glass table used for film coating with absolute ethanol, take 22cm*5.5cm aluminum foil, wipe the front and back with absolute ethanol, and lay the aluminum foil flat on the glass table to fix it firmly. Put an applicator on the aluminum foil with the 300um side down, pour the stirred slurry on the copper foil along the inner wall, pull the applicator in one direction at a constant speed, and then place the coated copper foil at 90 ℃ Bake for 4 hours, fill in the recording time of the coating film, and after baking, the pole piece is taken out and rolled.

3.3 Rolling pressure: Put the dried positive and negative plates on the roller machine, and the roller pressure is 3MPa.

3.4 Shotgun film: Prepare 22*5.5cm clean white paper and tweezers, take out the dried copper foil from the oven, use a 14mm manual punching machine to punch round diaphragms, punch 8 circular diaphragms per sheet of aluminum foil, Put the punched diaphragm into a dry weighing bottle, weigh the pole piece and put it in a 90°C oven to bake for one night, fill in the film baking time record form, and immediately transfer it to the glove box to cool. assembly.

3.5 Assembly: Move the baked membrane into a glove box with water and oxygen content of ≤5ppm, and place the negative shell of the 2032 button battery shell in parallel on the platform covered with clean paper. Place a nickel mesh in the negative electrode shell, add a few drops of electrolyte, then place the gasket, lithium sheet, drop 2 drops of electrolyte and place the diaphragm, pay attention to place the diaphragm in the center, and then add 2 drops of electrolyte Put the punched negative pole piece in the center, cover the positive steel shell, and seal it with a sealing machine at a pressure of 50 MPa.

3.6 Test: Put the prepared button battery on the Xinwei 5V10mA test cabinet for testing.

The positive test process is 0.1C constant current charging to the upper limit voltage of 4.2V, constant voltage charging until the current drops to 0.03C, set aside for 5 minutes, and 0.1C current constant current discharge to the lower limit cut-off voltage 2.0V, changing the charge and discharge current value to complete 0.2 C and 0.5C current value test.

4 Result calculation:

Positive/negative gram capacity = actual battery capacity / (pole piece mass - aluminum foil mass) × 100%.

5 Notes:

5.1 The positive electrode and carbon black must be dried for moisture when batching.

5.2 The pole piece must be flat when coating, and the surface of the pole piece must be absolutely clean, free from dust, moisture and alcohol.

5.3 During the assembly process, the assembly sequence and the cleanliness of each component should be guaranteed.