High nickel battery cells pack more energy, and lose it faster each cycle

More energy for the same weight

A battery cathode is the part inside a cell that stores energy while the battery is charged. Chemistry, in this case, means the specific mix of metals used inside that cathode. Specific energy measures how much energy a battery can store for every kilogram it weighs, in watt hours per kilogram. Battery University, a technical reference published by battery testing company Cadex Electronics, states that a cathode called nickel cobalt aluminium, or NCA, commonly 80% to 91% nickel, stores 200 to 260 watt hours per kilogram. A cathode called nickel manganese cobalt, or NMC, stores less, 150 to 220 watt hours per kilogram. Taking the middle of each range, NCA stores about 24% more energy for its weight, a MAOWCE calculation from 2 Battery University figures.

NCA also costs less to build. A kilowatt hour is the unit that measures how much energy a battery can hold. Battery University states NCA costs 350 dollars for every kilowatt hour of capacity, against 420 dollars for NMC, about 17% cheaper, another MAOWCE calculation from the same source.

Why automakers made the trade

The European Commission Joint Research Centre states that automakers have been choosing higher nickel versions of NMC chemistry specifically for higher energy density and longer distance per charge. Nickel also costs less than the cobalt it replaces. Cobalt is a metal inside the cathode that raises both cost and supply risk. In a version of NMC called NMC111, cobalt makes up 30% of cathode weight, and the cobalt price accounts for 11.60% of total cell cost, according to the Joint Research Centre. In NMC811, the highest nickel version in the same data, cobalt price accounts for just 2.70% of cell cost, a fall of 8.9 percentage points, a MAOWCE calculation from 2 Joint Research Centre figures.

What the trade costs

More nickel does not come free. A 2025 study in the journal Micromachines tested 6 versions of NMC chemistry, from NMC111 up to an 89% nickel version the study calls NMC89, and measured how much capacity each version lost with every charge and discharge cycle, called the capacity fade rate. The fade rate climbs almost in a straight line as nickel content rises, from 0.00522% per cycle at 50% nickel, NMC532, to 0.0362% per cycle at 89% nickel, almost 7 times higher, a MAOWCE calculation from 2 figures in the same study. The study notes 1 exception. The 33% nickel version, NMC111, fades faster than its own nickel content would predict, which the study attributes to thinner long term test data in the wider research literature rather than a real reversal of the trend.

Nickel rich cathodes also carry a safety cost. Battery University states NMC reaches 210 degrees Celsius before thermal runaway, the point where chemical reactions inside a cell start generating heat faster than the heat can escape. NCA reaches thermal runaway at a lower temperature, 150 degrees Celsius. A 2025 review in the journal Chemical Reviews and the United States Department of Energy both state, independently, that nickel rich cathodes carry a higher risk of thermal runaway. The Department of Energy states the same cells are also prone to rapid capacity fade.