GB/T 47401-2026Test method for lithium-ion battery cathode materials - Determination of slurry viscosity (English PDF)

1 Scope

GB/T 47401-2026 is the Chinese national standard covering the viscosity of a cathode slurry - the property that decides whether the coating goes down evenly on the foil, and therefore whether the electrode has uniform capacity across its width. First edition, in force since 1 October 2026. It was issued on 31 March 2026 and takes effect on 1 October 2026, as a first edition. The document is under the responsibility of the China Nonferrous Metals Industry Association. This page is published from the official record of the 2026 edition; the clause text of a standard this recent is not yet in circulation, and the figures, limits and tables it contains are those of the document itself, delivered in full with the English translation.

This document describes a method for determining the paste viscosity of cathode materials of lithium-ion battery using a viscometer and rheometer. This document applies to the determination of the paste viscosity of cathode materials of lithium-ion battery, including lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium cobalt oxide, lithium iron phosphate, and lithium manganese iron phosphate.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 8170 Rules of rounding off for numerical values & expression and judgement of limiting values

3 Terms and definitions

For the purpose of this document, the following terms and definitions apply.

3.1 viscosity internal friction Properties of a liquid substance under stress during deformation.

3.2 shear rate Velocity gradient of a liquid flow. NOTE. The unit of shear rate is s^-1.

3.3 non-newtonian liquids Liquids whose viscosity changes with shear rate and shear time.

4 Principle

Paste of cathode materials of lithium-ion battery is a non-Newtonian liquids. After pretreatment, the cathode materials are made into a paste with a certain solid content, which is placed in a viscometer or rheometer, and shearing is generated through rotational motion to determine the viscosity characteristics of the sample.

5 Reagents or materials

5.1 Cathode materials of lithium-ion battery. Lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium cobalt oxide, lithium iron phosphate, lithium manganese iron phosphate, etc.

5.2 Conductive agents. Carbon conductive agents, acetylene black or carbon nanotubes, battery grade.

5.3 Polyvinylidene fluoride (PVDF). Battery grade, weight-average molecular weight not less than 1 × 10^5, moisture content not greater than 0.10 %.

5.4 N-Methylpyrrolidone (NMP). Battery grade, purity not less than 99.99 %, moisture content not greater than 0.02 %.

7 Test conditions

7.1 Paste temperature. (25 ± 0.5) °C.

7.2 Ambient relative humidity. not greater than 5 %.