What Is Battery Supply Chain Due Diligence and Why It Matters

Cobalt sulfate is produced by dissolving heterogeneous feedstock in sulfuric acid, running the solution through solvent extraction to remove impurities, and recrystallizing the target compound. The feedstock entering a refinery in Kokkola, Finland, or Quzhou, China, on any given day might include copper-cobalt concentrate from an industrial mine operated by Glencore's Katanga Mining subsidiary, cobalt hydroxide aggregated through a chain of buying houses in Kolwezi where artisanal material mixes with industrial material at the point of first sale, recycled cobalt from a Belgian processor, and stockpiled intermediates purchased opportunistically from a trader in Durban whose documentation on origin is thin. All of it goes into the same circuit. What comes out is uniform. No isotopic ratio, no trace element profile, no spectroscopic signature survives full hydrometallurgical refining in a form that allows attribution of the output to any particular input stream. This has been tested. The isotopic fingerprinting research that generates periodic optimism in supply chain technology circles works on raw ore and on lightly processed intermediates, with reference databases that remain incomplete for most battery minerals. After refining, the technique fails for attribution purposes.

When a company says its cobalt is "fully traceable from mine to cathode," the statement means that a mass balance bookkeeping system assigns a proportion of certified input to a corresponding proportion of output. The atoms in the battery could have come from any input stream that entered the refinery during the production window. Mass balance is how palm oil certification works, how cocoa certification works, how the entire certified commodity economy works, and the gap between the consumer's intuitive understanding of "traceable" and what mass balance actually delivers has been a known problem in commodity certification for over a decade. The battery industry imported the model wholesale and inherited the credibility gap with it.

Blockchain makes the credibility gap worse, specifically, by adding technological gravitas to a system whose failure point is not data transmission integrity, which is what blockchain addresses, but data accuracy at the first point of entry, which is what blockchain cannot address. A buying house that enters false origin data into a blockchain traceability platform produces a cryptographically immutable record of a lie. That several major consulting firms continue to sell blockchain-based mineral traceability solutions to battery companies reflects the incentive structure of the consulting market. The companies buying these solutions are purchasing defensibility for their next sustainability report, not purchasing knowledge about where their minerals come from.

Now, why cobalt specifically has received so much more due diligence investment and infrastructure than any other battery mineral. Amnesty International's "This is What We Die For," published in 2016, documented child labor at artisanal cobalt mines in Katanga and traced supply chain linkages through buying houses and Huayou Cobalt's refining operations to specific consumer electronics and automotive brands. The report worked because it named companies. Reputational exposure at the brand level is the only mechanism that has consistently produced institutional responses in commodity supply chain governance. The Kimberley Process exists because advocacy campaigns named diamond retailers. Cocoa industry child labor programs exist because BBC and Channel 4 documentaries named chocolate brands. Garment factory safety reforms in Bangladesh accelerated after the Rana Plaza collapse killed 1,134 workers in a building producing clothes for identifiable Western retailers. The pattern is consistent: diffuse, well-known problems generate diffuse, insufficient responses until someone publishes an investigation that connects the problem to a consumer-facing brand name with something to lose.

The post-2016 cobalt due diligence infrastructure is substantial. RMAP extended to cobalt refiners. The Fair Cobalt Alliance built formalization programs at artisanal mine sites in the DRC. Huayou's CDM subsidiary established model mine operations with age verification and protective equipment at buying points. BMW, BASF, Samsung SDI, and others ran a pilot project attempting to trace cobalt from Katanga through the refinery and into the cell. The question is what all of this has changed at the point of extraction. Formalized sites are improved. Documentation exists at affiliated buying points. Age screening happens. The coverage of these programs relative to total artisanal cobalt output in the DRC is not a number that appears in corporate sustainability reports. In RMI working group discussions, which operate under Chatham House rules, the coverage question is discussed with a bluntness that the public-facing documents do not reflect. A formalization program covering a fraction of artisanal production, in a context where unaffiliated production migrates to less monitored channels, generates improvement within its perimeter and displacement outside it. This pattern is familiar from conflict minerals, from timber certification, from cocoa. The people designing battery cobalt programs are often the same people who designed those earlier programs, and they know the pattern. The constraints are not analytical. They are structural: no company can formalize an entire national artisanal mining sector, the DRC government lacks the capacity and in some cases the political will to do so, and the commercial pressure to secure cobalt volumes does not pause while governance catches up.

Indonesian nickel processing is where due diligence problems are accumulating fastest with the least institutional response, and explaining why requires explaining an infrastructure mismatch.

The due diligence apparatus built around cobalt was designed for upstream risk: conditions at mines far removed from the refinery. The risk at Indonesian nickel facilities is at the processing site. The buildout of HPAL and matte conversion capacity at Morowali and Weda Bay between 2018 and 2024, backed by Chinese capital, created laterite nickel processing at enormous scale. The environmental issues at these sites are not upstream sourcing questions. They are operational realities at the plant: rainforest overburden removal, acidic tailings containment in seismically active tropical terrain, coal-fired power loading the nickel with carbon intensity that will create problems under the EU Battery Regulation's carbon footprint requirements, deep-sea tailings discharge at some operations. The January 2024 Morowali smelter explosion killed over 20 workers. Indonesian labor groups had flagged conditions at the industrial park before the incident.

Amnesty, Global Witness, IPIS, SOMO built Katanga-focused research programs over years with dedicated funding streams. There is no equivalent institutional concentration on Indonesian nickel. Investigative journalism and Indonesian labor organizations have produced important reporting on Morowali and Weda Bay, but without the sustained institutional backing that Katanga-focused work has. The due diligence industry follows the advocacy infrastructure, the advocacy infrastructure follows the funding, and the funding follows the public narrative. Cobalt has a public narrative built on the image of children in mines. Nickel does not have a comparable narrative yet, despite the accumulation of environmental and labor evidence that, in aggregate, is at least as severe.

FEOC adds a layer. Several Indonesian facilities have ownership or financing relationships that intersect with IRA Foreign Entity of Concern definitions. Automakers using Indonesian nickel in US-market vehicles must run corporate genealogy analysis on the ownership chain while simultaneously assessing environmental and social conditions at the processing site. In practice, the FEOC corporate analysis gets priority staffing and budget because losing $7,500 per vehicle in tax credits shows up in the next quarterly earnings report. The environmental and social assessment gets what resources remain. This is not a secret inside the companies doing this work. It is the revealed preference of organizations that face one risk with quantifiable financial consequences and another with probabilistic reputational consequences.

The EU Battery Regulation mandates due diligence on cobalt, lithium, nickel, natural graphite, and manganese for any battery placed on the EU market regardless of manufacturing location. Carbon footprint declarations, recycled content thresholds, battery passports. The regulation is extraterritorial: Chinese and Korean cell manufacturers exporting to Europe must comply. The IRA works through tax credit conditionality and FEOC exclusions. Together, the two regimes have triggered the largest supply chain restructuring exercise in automotive history. Joint ventures renegotiated, offtake agreements rerouted, holding companies created in jurisdictions chosen for their FEOC definitional implications. Much of what is currently billed as battery supply chain due diligence at major law firms is FEOC compliance work.

The EU regulation's recycled content mandates face a timing problem. EV batteries last a decade or more. End-of-life EV batteries will not be available at scale until the mid-2030s. Near-term recycled content volumes will come primarily from pre-consumer manufacturing scrap: reprocessed production waste from cell lines. Efficient manufacturers recover this scrap regardless of any mandate. Whether it should count toward recycled content targets on the same basis as post-consumer material is a question that consumer advocacy groups have not yet focused on but will.

Lithium in the Atacama is about water depletion affecting Atacameño communities and the contested hydrogeology of brine-freshwater aquifer interactions. Chile's 2023 national lithium strategy requiring state participation in future projects reflects the political escalation. Graphite spheroidization is over 90% in China; environmental enforcement shutdowns in Heilongjiang and Shandong in 2017-2018 demonstrated both pollution severity and supply fragility. Manganese gets no systematic due diligence from anyone, despite opaque Gabonese supply chains, because the commodity margin does not justify the investigation cost and no NGO has published the kind of named-brand investigation that forces a response.

The reason all of this matters beyond the compliance department: battery manufacturing needs to scale from roughly one terawatt-hour of annual capacity to tens of terawatt-hours for decarbonization scenarios to hold. That means new mines in the DRC, Indonesia, Chile, Argentina, Australia, Mozambique, Zimbabwe, and elsewhere. Communities near proposed projects are opposing permits and filing legal challenges at rates that are extending project timelines years beyond initial forecasts. The constraint on the energy transition is not geology, technology, or capital. The constraint is that communities with generational experience of extractive industries have specific, evidence-based reasons to doubt that governance systems will protect them. Due diligence, performed seriously, is the only mechanism available for building that trust incrementally. The industry's current average level of practice is not sufficient to do so.