Test Methods for Anode Active Material

1.Determination of iron content in anode graphite

The sample to be measured was dissolved under the condition of heating (1+1) HCl solution, and then the concentration of iron content in the sample to be measured was measured by atomic absorption spectrophotometer standard curve method.

Apparatus: Atomic absorption spectrometer, analytical balance, electric furnace, 250mL volumetric flask, 100mL volumetric flask, beaker, glass rod, funnel

Reagent: AR (1+1) hydrochloric acid

（1）Prepare standard solutions of Fe, 0 ppm, 0.5 ppm, 1 ppm and 1.5 ppm.

（2）About 5 g of graphite was weighed in a 150 mL beaker in an analytical balance, 80 mL (1+1) of HCl was added and heated on a heating plate for about 30 min; the heated sample was cooled and filtered, fixed into a 100 mL volumetric flask, and the iron content was measured by atomic absorption spectrometry.

（3）Turn on the computer→Open the instrument→Enter the working software→System reset (reset once per power on)→Tap OK after the reset is completed→Element selection→Condition setting→Wavelength positioning→Automatic energy to about 100%.

（4）Open the air valve, adjust the output pressure 0.2~0.3MPa, then open the acetylene valve, adjust the pressure to 0.05~0.1MPa, press the host acetylene switch, adjust the acetylene switch to make the acetylene flow to the scale line, and ignite immediately.

（5）The testing sequence is specimen blank→specimen blank→sample blank→sample test.

Calculation：

2.Test method for particle size of negative graphite

In the propagation of light, the wave source is restricted by the gap or particle of the same wavelength scale, and the emission of each element wave at the restricted source interferes in space to produce diffraction and scattering, and the spatial (angular) distribution of the diffracted and scattered light energy is related to the wavelength of the light wave and the scale of the gap or particle. With laser as the light source, the light is monochromatic with a certain wavelength, and the spatial (angular) distribution of diffracted and scattered light energy is only related to the particle size. For the diffraction of the particle group, the amount of each particle level determines the size of the light energy obtained at each specific angle, and the proportion of each specific angle light energy in the total light energy should reflect the distribution abundance of each particle level.

Instruments:laser particle size analyzer, ultrasonic cleaning machine, glass rod, beaker

Reagent: Glycerol solution

（1）Check whether the instrument power supply and water source are well connected. Turn on the power of the host (preheat for 30 minutes), then turn on the computer in turn to enter the instrument operation interface and turn on the water source.

（2）Configure the dispersant: add a few drops of propanetriol to a 150mL beaker, dilute to 50mL with water, and mix well.

（3）Sample preparation: add an appropriate amount of sample to the beaker, moisten with a small amount of water, add a few drops of dispersant, stir and mix, dilute with water to about 80mL, and put the beaker into the ultrasonic cleaner for 3-4min.

（4）Preparation of the instrument: Align the system (once each time you turn on the instrument)→Set the parameters (choose graphite, refractive index 2.4)→Click "New" to create a blank report→Prepare the sample, click "Auto" when the ultrasonic time of the sample is about 1 minute left, and wait for When the instrument informs you to feed the sample, pour the sample into the circulating sampler and rinse the beaker with water.

Calculation:automatically generated by the instrument

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