| Material type and intended use | Identify natural or synthetic graphite, product form, intended process, and application-specific requirements. | Product specification, production route description, and a representative sample from the proposed product. | Confirm the quoted material matches the required feedstock. Do not treat natural and synthetic graphite as interchangeable without application testing. |
| Carbon content and ash | State whether the requirement is total carbon or fixed carbon, the reporting basis, units, test method, and lot limit. | Lot-specific certificate of analysis (COA), test method, and laboratory identification. | Compare results only when test methods and reporting bases are consistent. Set limits to match the end-use process rather than relying on a generic grade description. |
| Moisture and volatile matter | Define maximum moisture and, where relevant, volatile matter, including the test conditions and reporting basis. | Recent COA results and documented sampling and storage practices. | Check that results are within the agreed limits and that packaging protects the material from moisture during storage and transport. |
| Particle-size distribution | Specify the required size range or D10, D50, and D90, plus the measurement method and dispersion conditions where relevant. | Lot-specific particle-size report and method details, such as sieve analysis or laser diffraction. | Verify that the reported distribution—not only a nominal mesh or median size—fits the mixing, forming, or processing requirements. |
| Impurity profile | Identify critical elements for the application and define limits in appropriate units, such as mg/kg or percent. | Elemental analysis report, analytical method, detection limits, and the list of elements tested. | Check that the reported detection limits are sufficiently low to assess the agreed limits. Request additional testing for application-critical contaminants. |
| Physical and functional properties | Where relevant, specify bulk or tap density, specific surface area, particle morphology, or electrical properties. | Test results tied to a stated method, sample preparation, and material lot. | Include only properties that affect the application. Compare supplier results using equivalent methods and test conditions. |
| Lot consistency and sampling | Define lot size, sampling plan, retention-sample requirements, and how out-of-specification results are handled. | Written quality-control procedure, sample records, and trend data across multiple production lots. | Review variation across lots, not just a single sample. Confirm that the buyer can inspect or independently test representative material. |
| Traceability and origin | Require a traceable link from the delivered lot to its production site, source or feedstock category, and processing history. | Lot identifiers, batch records, packing-list references, and documented chain-of-custody information. | Check that identifiers agree across the COA, packaging, invoice, and shipping documents. Ask the supplier to explain any gaps in origin or processing records. |
| Quality management and change control | Agree on notification requirements for changes to feedstock, processing, test methods, production site, or specification. | Quality-system documentation, nonconformance procedure, and written change-control process. | Confirm that changes affecting material properties require advance notice and, when needed, requalification before shipment. |
| Supplier qualification and incoming inspection | Set a qualification plan, required documents, sample approval process, and risk-based incoming testing frequency. | Pre-shipment sample, current COA, agreed specification, and corrective-action contact process. | Approve the material against the buyer’s own requirements and verify selected lots through independent or incoming testing. |
