Cobalt is important because it plays essential roles across human biology, energy technology, aerospace, and medicine. It is one of the few elements that your body literally cannot function without, and it is also a critical material in the rechargeable batteries that power smartphones and electric vehicles. Its unique combination of properties, from magnetic strength to heat resistance to electrochemical stability, makes it difficult or impossible to fully replace in many applications.
Cobalt in Your Body: The Core of Vitamin B12
Cobalt sits at the center of the vitamin B12 molecule, making it one of the rare metals that plays a direct role in human biology. Every form of B12 is built around a single cobalt atom, and without it, the vitamin cannot function. B12 is found in every cell in your body, where it acts as a helper molecule in DNA synthesis and keeps your nervous system running properly. A cobalt deficiency, in practical terms, means a B12 deficiency, which leads to fatigue, nerve damage, and a type of anemia where your red blood cells grow abnormally large.
You only need trace amounts of cobalt through your diet, and virtually all of it arrives packaged inside B12 from animal products like meat, eggs, and dairy. The element itself isn’t something you’d want to take as a supplement. In fact, absorbing too much cobalt over time causes serious problems: heart muscle weakness, thyroid dysfunction, nerve damage, hearing loss, and vision problems. Cobalt was once used as a foam stabilizer in beer, which led to a condition known as “beer-drinker’s heart,” where the heart became enlarged and struggled to pump blood effectively. Breathing in cobalt dust in industrial settings can also cause chronic lung disease resembling asthma or pulmonary fibrosis.
Why Batteries Depend on Cobalt
The biggest source of modern cobalt demand is lithium-ion batteries. Cobalt helps create cathodes (the positive terminal of a battery) with the highest volumetric energy density available, meaning they store more energy in less space. In the cathode chemistry known as LCO, which dominates the consumer electronics market, cobalt delivers high operating voltage, excellent electrical conductivity, and strong capacity retention over hundreds of charge cycles. This is why your phone, laptop, and tablet can hold a charge as long as they do in a thin, lightweight package.
Electric vehicle batteries take this to a much larger scale. An EV battery pack can contain up to 20 kilograms of cobalt in a single 100-kilowatt-hour pack. In EV cathode chemistries that blend nickel, cobalt, and manganese, the cobalt component specifically enhances thermal stability (reducing fire risk), improves performance in cold weather, and helps the battery deliver power quickly when you accelerate. Without cobalt, these batteries would degrade faster, overheat more easily, and lose capacity sooner.
That said, cobalt’s cost and supply chain concerns have pushed the industry toward alternatives. The cobalt-free battery market, led by lithium iron phosphate (LFP) chemistry, reached roughly $1.83 billion in 2025 and is projected to grow to $5.77 billion by 2035. LFP batteries are cheaper and thermally stable, though they store less energy per unit of volume. About 65% of cobalt-free battery demand comes from electric vehicles, a sign that some automakers are willing to trade range for lower cost and simpler supply chains.
Superalloys That Survive Extreme Heat
Cobalt-based superalloys are engineered for environments where most metals would soften or corrode. These materials can withstand severe mechanical loads at temperatures above 800°C, and they outperform nickel-based superalloys in several important ways. Cobalt alloys form dense, slow-growing protective oxide layers on their surfaces that resist hot corrosion in aggressive chemical environments far better than competing materials. They also offer superior creep resistance above 1,000°C, meaning they hold their shape under sustained stress at extreme temperatures, along with better weldability and resistance to thermal fatigue from repeated heating and cooling cycles.
Newer tungsten-free cobalt superalloys have achieved remarkably high strength-to-weight ratios, making them promising candidates for gas turbine blades in jet engines and power plants. While nickel-based superalloys still dominate the most critical turbine blade applications due to higher raw mechanical strength, cobalt alloys fill roles where corrosion resistance and thermal cycling matter more than peak load capacity.
Magnets for Extreme Conditions
Cobalt is one of only three elements (along with iron and nickel) that are naturally magnetic at room temperature, and it retains its magnetism at higher temperatures than either of the others. This property makes it essential in two families of permanent magnets: Alnico (aluminum-nickel-cobalt) and samarium-cobalt.
Samarium-cobalt magnets are particularly valued where performance cannot be compromised. They power high-performance motors, generators, gyroscopes, accelerometers, and sensor systems. They show up in military applications like missile guidance components and radar-absorbing coatings for stealth aircraft, where samarium-cobalt material absorbs electromagnetic waves to reduce radar signatures. In medicine, they’re used in devices that must deliver strong, stable magnetic fields in compact form factors. Their ability to maintain magnetic strength at temperatures that would weaken other magnets makes them irreplaceable in turbomachinery, drilling equipment, and particle accelerators.
Cancer Treatment With Cobalt-60
A radioactive form of cobalt, cobalt-60, has been used in cancer treatment for decades. It produces high-energy gamma rays that can be directed at tumors to destroy cancer cells. Cobalt-60 units were among the first sources of external beam radiation therapy and remain in use worldwide, particularly in regions where more expensive linear accelerators are unavailable. Research has also demonstrated that cobalt-60 can serve as a radiation source for medical imaging during treatment, allowing clinicians to see tumors in real time while delivering precisely shaped radiation doses.
A Concentrated Global Supply
One reason cobalt commands so much strategic attention is where it comes from. The Democratic Republic of the Congo accounted for 74% of global cobalt mine production as of 2024, with Indonesia a distant second at 7%. This extreme geographic concentration creates supply chain vulnerability for every industry that relies on the metal. Disruptions from political instability, labor practices, or export policy changes in a single country can ripple through battery manufacturing, aerospace, and electronics worldwide.
This supply risk is a major driver behind efforts to develop cobalt-free battery chemistries and to improve cobalt recycling from spent electronics and EV batteries. For now, though, the combination of properties cobalt offers, from electrochemical stability to heat resistance to biological necessity, keeps it among the most strategically important metals on Earth.