The two most visible niobium-to-AI infrastructure deals of the past six months both have the same Brazilian supplier inside them. On November 11, 2025, Skeleton Technologies opened a one-gigawatt-per-year SuperBattery factory in Varkaus, Finland, naming CBMM as the partner supplying the niobium oxide that runs through its cells [Skeleton Technologies press release, November 11, 2025]. Six months later, on May 6, 2026, the Cambridge battery startup Nyobolt closed a $60 million Series C at a $1 billion valuation, led by Symbotic, with CBMM participating alongside IQ Capital, Latitude (Phoenix Court), and Scania Invest [Nyobolt press release, May 6, 2026]. Two distinct anode chemistries, one common input, one common Brazilian source.

What’s happening

Why niobium fits the AI data center backup problem

GPU clusters running large training and inference workloads create instantaneous power demand spikes that conventional grid response cannot smooth and that conventional lithium-ion battery backup struggles to handle without fast-charge degradation. Niobium-oxide based anode chemistries admit lithium ions through surface-level intercalation rather than slow bulk diffusion, which allows fast charging without the lithium plating that shortens cycle life and creates thermal runaway risk in graphite-anode cells. The two companies have arrived at this from different chemistry routes: Skeleton uses niobium pentoxide via CBMM’s NBXCELER line; Nyobolt uses a niobium tungsten oxide anode. The commercial hook is the same: more cycles, faster charge, lower fire risk than the lithium-ion BBU baseline [Skeleton Technologies press release, November 11, 2025; Nyobolt press release, May 6, 2026].

Brazil angle

Brazil holds the overwhelming majority of known global niobium reserves (roughly 16 million tonnes out of a global total above 17 million) and accounted for approximately 92 percent of 2024 global mine production, with CBMM in Araxá the dominant single producer [USGS Mineral Commodity Summaries 2025, Niobium chapter]. Sixty-six percent of US total niobium material imports by content come from Brazil [USGS Mineral Commodity Summaries 2025]. This is the cleanest concentration story in critical minerals outside the China-DRC nexus, and unlike rare earths, neither Washington nor Brussels treats Brazilian concentration as a sovereignty problem. It is the alternative.

CBMM is now visible as more than a supplier. In a 2023 Fastmarkets interview the company’s executive manager for battery products stated a target of 25 percent of revenue from battery raw materials by 2030 and confirmed an $80 million investment in CBMM’s first industrial-scale battery-grade niobium oxide refining plant in Araxá, first production targeted at 3,000 tonnes per year from Q2 2024, with a stated 2030 ambition near 35,000 tonnes per year of battery-grade output compared to roughly 270 tonnes in 2022 [Fastmarkets, September 13, 2023]. The Skeleton offtake and the Nyobolt equity stake are how that strategy now shows up on the AI side of the market. CBMM is not just selling oxide. It is funding the downstream that consumes the oxide.

US angle

The US has not reported significant niobium mine production since 1959, and net import reliance has stayed at 100 percent of apparent consumption across 2020 to 2024 [USGS Mineral Commodity Summaries 2025, Niobium chapter]. The September 2024 US Department of Defense award of $26.4 million to a company in Boyertown, Pennsylvania to establish high-purity niobium oxide production is the closest the US has to a domestic midstream, alongside a separate Nebraska niobium project still working through financing [USGS Mineral Commodity Summaries 2025]. Niobec in Quebec is the only Western producer outside Brazil at scale, accounting for roughly 7 percent of global production. Any forward US niobium-anode capacity will plausibly run on imported feedstock for the foreseeable future. The dependency here is structural, not strategic: there is no Chinese alternative supply to displace.

China angle

Niobium is the unusual critical mineral where China is the dependent party. There is no Chinese domestic niobium project that rivals Araxá in scale or grade, and Beijing has not announced an export-control framework on niobium because the basket is largely outbound for China, not inbound. Chinese battery makers exploring niobium-containing chemistries continue to source the underlying input through Brazilian and Canadian producers. On the rare earth side the November 10, 2026 expiration of China’s October 2025 export-control suspension still hangs over the trade as a hard deadline [Mining Technology, May 2026; see Tantalum, May 28, 2026]. Niobium has no equivalent deadline because there is no equivalent Chinese chokepoint.

What it means

The Tantalum AI Materials Index carries niobium as an editorial proxy because the trade is private and there is no daily spot market. The Skeleton and Nyobolt deals do not change that data hygiene problem, but they tighten the read on what CBMM is doing with its capacity. The Southern Diversification Index, which includes a niobium constituent through the CBMM proxy, sat at 96.1 as of May 22, 2026, down 3.9 percent year to date, even as the operational story builds. TAI and SDX are thematic indexes that apply a documented editorial overlay; naive replication from public feeds alone will diverge. See /indexes/methodology.

What to watch