Chain of custody (CoC) documentation for cobalt tracks the material from mine to battery cell, providing evidence that cobalt has been sourced responsibly and that due diligence obligations have been met. The EU Battery Regulation's due diligence requirements (Articles 48–52) and battery passport (Article 77) create unprecedented CoC documentation requirements for cobalt.
CoC Models
Three CoC models are used in cobalt supply chains:
- Physical segregation: Cobalt from specific mines or regions is physically separated throughout the supply chain. Provides the strongest traceability but is operationally complex and costly.
- Mass balance: Volumes of responsibly sourced cobalt are tracked through the supply chain, but physical material may be commingled. The most common model used by refiners and cell manufacturers.
- Book and claim: Certificates of responsible sourcing are traded separately from physical material. Allows downstream companies to support responsible sourcing without direct supply chain control.
RMI CoRAP Certification
The Responsible Minerals Initiative (RMI) Cobalt Refiner Assessment Program (CoRAP) is the primary third-party audit program for cobalt refiners. CoRAP-conformant refiners have undergone independent audits against OECD due diligence standards. The RMI publishes a list of CoRAP-conformant refiners that downstream companies can use to verify their supply chains.
Cobalt Reporting Template (CRT)
The RMI's Cobalt Reporting Template (CRT) is the industry-standard tool for collecting supply chain information from suppliers. The CRT captures: cobalt-containing materials used; smelters and refiners in the supply chain; country of cobalt origin; and due diligence status of identified smelters/refiners. Companies should collect completed CRTs from all direct suppliers annually.
Documentation Requirements for EU Battery Regulation
For the EU Battery Regulation battery passport (from 2027), companies must be able to provide: cobalt content (kg per battery); percentage of recycled cobalt; country of cobalt origin; smelter/refiner identities; third-party audit status of smelters/refiners; and carbon footprint of the cobalt mining and processing stage.