Even though the term “lithium battery” is loosely applied to all types of batteries that use lithium in the cathode material, the truth is that there is considerable variation in battery chemistry, and while most rechargeable lithium batteries have a lot in common, the differences in battery chemistry gives each of them unique attributes and benefits.
Case in point, take lithium iron phosphate batteries, also known as LiFePO4 batteries or LFP batteries. These use lithium iron phosphate as a cathode material, and stand in contrast to other types of lithium batteries, such as lithium cobalt oxide and lithium manganese oxide.
This short post will break down some of the details so you can gather a better understanding of lithium battery chemistry.
Differences Between Lithium Iron Phosphate Batteries and Other Types of Lithium Batteries
Lithium iron phosphate batteries use lithium iron phosphate as the cathode material, and generally use a graphite carbon electrode for the anode material. The cathode is the positive terminal electrode where the reduction reaction occurs and the cell gains electrons, and the anode is the negative terminal.
Lithium iron phosphate, as a cathode material, is much more stable than many other types of lithium chemistry, especially lithium cobalt oxide, which is also a widespread cathode material.
Notably, lithium iron phosphate is more stable, even at high temperatures, than lithium cobalt oxide. When lithium cobalt oxide batteries are exposed to high temperatures, or overcharged, the chemical bonds in the cathode material can break down; when this happens, they get even hotter, which is known as thermal runaway, and which can cause fires with which some associate lithium batteries.
Unlike lithium cobalt oxide, LFP batteries have a much more stable battery chemistry that is resistant to higher temperatures as well as to overcharging. As a result, even when overcharged, there is a low risk of thermal runaway, which makes LFP batteries safer than other types of lithium battery chemistries.
Another difference between LiFePO4 batteries and other lithium batteries is that they have a relatively low specific energy, which is also referred to as gravimetric energy density. This metric gives an indication of how much energy, in a charge, a battery can hold relative to its weight.
It is important to note here that the low specific energy of LFP batteries is relative to other lithium batteries. Though other lithium batteries can hold more energy in comparison to their weight, LFP batteries still have a high energy density compared to conventional alternatives like lead-acid batteries.
Another difference between LFP batteries and some other types of lithium batteries is that their performance does drop in extremely cold temperatures. But, even with that being the case, it is important to note that many types of batteries suffer the same effects, so this is once again only a relative drawback.
Advantages of Lithium Iron Phosphate Battery Chemistry
Compared to other lithium batteries, lithium iron phosphate batteries offer some significant advantages. The main one, which has already been covered here, is safety, as the stable battery chemistry produces a lower risk of thermal runaway. In fact, some LFP batteries can even be charged to 100% without damaging the cell.
Like other lithium batteries, LFP batteries offer a relatively high energy density compared to lead-acid alternatives, as well as more consistent output as the charge level drops. This makes them excellent options for powering RVs, golf carts, and even as batteries for trolling motors.
There are also potential ecological advantages of lithium iron oxide chemistry. Other types of lithium batteries such as lithium cobalt oxide and lithium nickel manganese cobalt oxide involve the mining and refinement of heavy metals like nickel, manganese and cobalt, which are either themselves toxic, or which incur processes that can be environmentally harmful. The stakes associated with LFP batteries are lower and generally considered safer for the environment.
Some of the advantages of LFP batteries are also shared in common with other types of lithium batteries. These include low self discharge rate, which means that the batteries do not lose much of their charge when they are unused or in storage, as well as long lifespans.
Depending on conditions, a lead-acid battery can self-discharge at a rate ranging from 3% to as high as 15% per month, and many will only last through 200 to 500 charge cycles, although when properly cared for they can last longer. Many lithium batteries, including LFP batteries, will last through thousands of charge cycles (while maintaining much of their original capacity) and self-discharge at a rate as low as 1% per month.
All in all, these relative advantages make lithium iron phosphate batteries the safest choice in lithium battery chemistry for a wide range of residential, commercial and even industrial applications.
LFP Battery Benefits at a Glance
To summarize the majority of the information in this article, here are some of the high-level benefits of LFP batteries:
- LFP batteries have the safest, most stable cathode material among lithium batteries.
- LFP batteries have a low self-discharge rate.
- They offer a high energy density compared to lead-acid alternatives.
- They are reliable, durable, and have long battery lifespans.
- They retain a large amount of their original capacity even after thousands of discharge cycles.
- Unlike some other types of lithium battery chemistries, they are non-toxic, emission-free and generally more eco-friendly.
- They produce little heat during charging and discharging.
- They offer a relatively flat discharge curve, providing constant output even as the charge level drops.
Questions About LFP Batteries? Contact Us
Still have questions about LFP batteries, or about the different types of lithium battery chemistries? Get in touch with us for more information and we will be more than happy to help. Otherwise, take a closer look through our catalog of lithium batteries for golf carts, RVs, solar systems, marine applications and others to learn more about their unique benefits and use cases.
