Vanadium Flow Batteries and the Maracás Story

Brazil's largest primary vanadium operation, Largo Resources'

Maracás-Menininha in Bahia, sits at the intersection of two different

markets: traditional high-strength steel and the emerging vanadium redox

flow battery. The latter — specifically designed for long-duration grid

storage — could turn vanadium from a niche steel-alloying commodity into

a strategic energy-transition metal.¹

Largo at Maracás-Menininha

Largo Resources operates the Maracás-Menininha mine in the Maracás

region of Bahia, extracting vanadium from magnetite-rich ore through an

integrated mine-to-metal process. The operation produces vanadium

pentoxide (V2O5) and related vanadium products, and is one of the

largest primary vanadium producers in the world — by volume and by

product purity.¹

Commercial production began in 2014, and the operation has consistently

ranked among the lowest-cost global producers since. The ore grade and

the processing approach combine to produce vanadium at unit costs that

compete with Russian co-product vanadium and Chinese steel-slag-derived

production. For a commodity where cost differences between producers can

be substantial, Maracás-Menininha's position is meaningful.

Largo has also invested in downstream capability. The company has

developed its own vanadium redox flow battery technology and has

commissioned initial installations for specific grid-storage

applications. That integration — from mine through chemical processing

to finished battery — is unusual for a mining company of Largo's size

and reflects a specific strategic bet on vanadium's role in

long-duration storage.

How Vanadium Redox Flow Batteries Work

Vanadium redox flow batteries (VRFB) use liquid electrolytes — vanadium

dissolved in sulphuric acid — stored in separate tanks and circulated

through an electrochemical cell stack. Because the vanadium is in

solution rather than in a solid cathode, the battery's energy capacity

is determined by tank size rather than by the cell stack, which allows

for very large energy-to-power ratios not achievable in lithium-ion

designs.

That structural property makes VRFBs particularly suited to

long-duration grid storage. A lithium-ion battery optimised for 4-hour

storage uses the same cell chemistry regardless of duration, making

longer-duration applications progressively more expensive. A VRFB scaled

for 8, 10 or 12-hour storage simply uses larger electrolyte tanks — a

fundamentally more economic design for long-duration applications.

VRFBs also offer very long cycle life (30 years or more), minimal

degradation with depth of discharge, and excellent safety

characteristics. The electrolyte is non-flammable, the system operates

at ambient temperature, and the environmental footprint is smaller than

lithium-ion alternatives.

The Grid-Storage Opportunity

Grid-scale energy storage is one of the fastest-growing segments of the

broader electricity sector. Benchmark Mineral Intelligence reported that

global battery energy storage system (BESS) demand jumped 51 percent in

2025, with total installations exceeding 315 GWh across grid-scale and

behind-the-meter markets.² Most of that capacity was

lithium-iron-phosphate, but the long-duration segment — where VRFBs have

structural advantages — is itself projected to grow rapidly through 2030

as renewable-energy penetration reaches the levels that require

multi-hour firming.

China has led VRFB deployment to date, with several large installations

(100-200 MWh each) operational across the country. European and North

American deployments have been smaller but are accelerating,

particularly for pairing with utility-scale solar and wind projects

where 8-hour or longer storage is increasingly economically attractive.

If VRFBs capture even 10-15 percent of the long-duration-storage market

by 2030, the implied vanadium demand would materially exceed current

global production. That scenario would substantially reshape

vanadium-market pricing and would make producers like Largo highly

strategically valuable.

Global Vanadium Context

Top global vanadium producers are China, Russia, South Africa and

Brazil. Global annual production sits at approximately 110,000-120,000

tonnes of vanadium content, with Chinese production often contributing

roughly half of the total. Much of Chinese vanadium output is a

co-product of steel-slag processing, which creates a specific cost

structure and supply behaviour that differs from primary vanadium mines.

Roughly 85-90 percent of global vanadium consumption currently goes into

high-strength low-alloy (HSLA) steels, used in construction, pipelines

and automotive applications. The remaining 10-15 percent is divided

across specialty alloys, chemical catalysts, titanium-alloy master

alloys and the growing VRFB segment. As VRFB demand scales, the share

distribution will shift accordingly.

Brazilian vanadium production from Maracás-Menininha, at approximately

10,000-12,000 tonnes of vanadium content per year, places Brazil

comfortably inside the global top five. Reserves in the region are

sufficient to support continued production at current rates for decades,

and additional Brazilian vanadium exploration projects exist at earlier

stages.

Brazilian Positioning

Largo's integrated strategy — mine, process, manufacture batteries — is

unusual in the broader mining industry and makes the company a case

study for how upstream critical-minerals producers can capture

downstream value. If VRFB adoption scales as optimists expect, Largo's

position is structurally attractive. If VRFB adoption remains modest and

lithium-ion continues to dominate long-duration storage, the battery

investment becomes a smaller side-line to the core steel-alloying

business.

For Brazilian industrial policy, Largo demonstrates that domestic

processing and manufacturing on top of mining is achievable even without

massive state-led industrial initiatives. A mid-sized listed mining

company with disciplined e

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