As more brands enter the market for high-capacity lithium-ion batteries to power heavy-duty equipment such as zero-turn lawn mowers, there is increased focus on battery chemistry. At Gear Expo 2022, there was a lot of talk about LFP versus NMC lithium-ion batteries after prototypes fired up on the outdoor booth. We're digging deeper to help you understand why your device's battery can be just as important as performance and features when you're looking for a heavier battery-powered device.
LFP VS NMC Li-Ion Batteries: Cathode Chemistry
Before we get into features, let's define LFP and NMC. Both are cathode options in the battery pack. If you remember from chemistry class, a battery consists of a cathode, an anode, and an electrolyte for the reacting part. The cathode is the positive electrode, the anode is the negative electrode, and the electrolyte helps facilitate the movement of ions across the separator to generate energy.
LFP batteries contain lithium iron phosphate cathodes. NMC batteries contain lithium nickel manganese cobalt oxide.
| Lithium iron phosphate battery | Ternary battery | |
| specific energy | 90 – 120 Wh per kg | 150 – 220 Wh per kg |
| cycle life | 2000+ cycles | 1000 – 2000 cycles |
| thermal runaway | 518°F (270°C) | 410°F (210°C) |
Advantages of LFP batteries
- More domestic materials
- lower cost
- higher ignition point
- longer life
- Less degradation at higher temperatures and charge/discharge rates
Advantages of NMC batteries
- higher energy density
- Better low temperature charging performance
Source: Engineering.com
As can be seen from the graph above, NMC batteries have more watt-hour capacity than LFP batteries when the mass is the same. In other words, packing the same weight of both options into a single battery yields a much larger NMC capacity.
However, LFP batteries have advantages in terms of overall longevity. LFPs are expected to have a life of at least 2000 cycles, with some estimates suggesting 3000 cycles, depending on the application. On the other hand, the NMC package expects 1000 to 2000 loops. Still, it's impressive.
Where things get more interesting is thermal runaway — when a battery goes into an uncontrollable self-heating state, with potentially dangerous consequences. This is one of the reasons we don't recommend using third-party chargers or batteries. LFP cells experience thermal runaway at 518° F (270° C), while NMC cells reach thermal runaway of more than 100° F at 410° F (210° C). The gap between the two makes a big difference when you're talking about high-capacity batteries where thermal management is a major challenge.
Combined with lower cost, less degradation at aggressive charge rates, and more domestically available materials, LFP is a very attractive option if manufacturers can overcome the lower energy density.
the bottom line
As the demand for higher density battery packs continues to grow, so will the NMC vs. LFP lithium-ion debate. Right now, the needs for the safest technology and the most energy-dense technology seem to be in conflict. Whether science can close the energy density gap, or another battery chemistry emerges, LFP batteries are currently the safest way to transition to battery-powered devices.