GB/T 33818-2017Carbon nanotube conductive paste (English PDF)

3.1 Carbon nanotube; CNT

Nanotubes made of carbon atoms.

3.2 Multi-walled carbon nanotubes; MWCNTs

The graphite sheets with three layers and above are curled into a coaxial nested quasi-one-dimensional tubular carbon nanomaterial.

3.3 Carbon nanotube conductive paste

A multiphase mixture that is consisted of carbon nanotube as the main solid component, that acts as a conductive medium, and that is composed with certain liquid.

4.1 Principles

Carbon nanotube technical requirements include general technical requirements and additional requirements for specific application fields. Carbon nanotube paste, on the basis of meeting the general technical requirements, should also comply to the appropriate additional technical requirements chosen by both supply-demand parties as per the use of this product.

4.2 General technical requirements

4.3 Additional technical requirements (applicable to the field of lithium ion batteries)

4.3.1 The viscosity value of the paste should be provided by the supplier after the calibration of the standard sample.

4.3.2 The total content of magnetic foreign matters (Fe, Cr, Ni, Zn, Co) in the paste should not exceed 0.002% (mass fraction) of the carbon tube content.

4.3.4 The water content in the anhydrous system should not be more than 2000 x 10^-6 (mass fraction). If the user has special requirements, it may be determined by consultation of both supply-demand parties.

4.3.5 The pH value of water-based paste should generally be within the range of 5.0~9.0.

5.1 Appearance

Visual inspection.

5.2 Solid content

Measure and calculate as per GB/T 1725.

5.3 Content of carbon nanotubes

5.5 Transmittance

5.5.1 Instruments and materials

Ultrasonic cleaner, UV-VIS spectrophotometer, high speed mixer (maximum speed at least 3000rpm), cuvette and other auxiliary appliances.

5.5.2 Pre-test preparation

5.5.2.1 Use the ultrasonic cleaner to clean the 1cm cuvette liquid pool and the glass instruments to be used, and dry them.

5.5.2.2 Turn on the UV-VIS spectrophotometer, which can be used to measure after stabilizing for 30min, and set the wavelength to 546nm.

5.5.3 Test steps

5.5.3.4 Seal the diluted solution and stir it at the speed of 3000r/min for 30min± 0.1min, and then, after the stirring, place it for settlement for 10min.

5.5.3.5 Suck the supernatant with a suction tube to clean the cuvette pool, and wipe clean the outer wall of the pool with lens wiping paper.

5.5.3.6 Suck again the supernatant, put it into the liquid pool with the suction tube. The liquid level is 2/3 of the height of the cuvette pool, then place it in the UV-VIS spectrophotometer. Read the transmittance value after the value is stable.

5.5.4 Result calculation

5.6 Volume resistivity

5.6.1 Instruments and materials

Four-probe resistivity meter, air dry oven, press machine, glass plate, standard scraper coater, high temperature resistant polyester film (PET film) and other auxiliary tools.

5.6.2 Preparation of sample slice

5.6.2.1 Seal the sample in a self-sealing bag, then stir for 5min with a glass bar to make the paste in an even state.

5.6.2.5 Use a spiral micrometer to measure the thickness of the compacted paste on the sample film. Measure 3 different points and take the average value.

5.6.2.6 Use the four-probe resistivity meter to test the volume resistivity of the sample, select the appropriate range, input the thickness of the paste and the diameter of the wafer (15mm) to the parameter settings of the tester, other parameters are automatically selected by the tester.

5.6.3 Result calculation

5.7 Viscosity

It is measured according to the requirements of rotary viscosity measurement method in GB/T 22235-2008.

5.8 Magnetic foreign matters content

This test shall be determined through consultation of both supply-demand parties. After consultation, it can also be carried out in accordance with the method in Appendix A.

5.11 pH value

It is determined according to the requirements in QB/T 2303.10.

6.1 Grouping of batches

6.2 Sampling quantity

At least 3 samples per batch.

6.3 Test items

6.3.1 Test classification

The product inspection stipulated in this standard is divided into batch inspection and type inspection.

6.3.2 Batch inspection

6.3.3 Type inspection

When the type inspection is in the case of any of the following circumstances, all the technical requirements stipulated in this standard should be tested.

6.3.4 Items of batch inspection and type inspection

See Table 1 (example of lithium ion battery applications).

6.4 Inspection and acceptance

6.4.1 Products shall be inspected by the supplier's quality supervision department to ensure that the quality of the product meets the requirements of this standard or order contract, and the quality certificate should be filled in.

6.4.2 When the paste product is not qualified in appearance inspection, the quality of the products is deemed not qualified.

6.4.3 If the paste product is not qualified in any test of the composition, fineness, relative absorbance and the conductivity etc., the product is not qualified.

7.1 Packing and marking

7.1.1 After inspection, the qualified products are packed generally 20L~50L as a package. The packing should be tight; the outer wall of the packing bucket should be labeled with exit-warehouse label with information as follows.

7.1.2 If the customer has specific requirements, corresponding packaging and logo design can be carried out.

7.1.3 When supplied, every batch of products should be accompanied with the < carbon nanotubes conductive paste inspection report >, with content including the relevant technical parameters of the batch products.

7.1.4 Each batch of products is accompanied by < shipping list>, with content including but not limited to the following items. […]

7.2 Transport and storage

7.2.1 The product is suitable for storage at normal ambient temperature. The warehouse should be ventilated and dry. Under the required condition of packing and storage, the quality guarantee period should be no longer than 12 months from the date of production.