What is the negative electrode material of lithium iron phosphate batteries?
2 Answers
This type of lithium battery generally uses graphite for its negative electrode. Graphite has a layered structure, which allows it to accommodate lithium atoms. Most lithium batteries use graphite for their negative electrodes. The positive electrode of lithium iron phosphate batteries is made of lithium iron phosphate, and this type of battery is commonly found in many pure electric buses. More details are as follows: Classification of lithium batteries: There are two types of lithium batteries commonly used in pure electric vehicles: ternary lithium batteries and lithium iron phosphate batteries. Ternary lithium batteries: The negative electrode of ternary lithium batteries is mostly made of graphite, while the positive electrode is made of ternary materials. Some ternary lithium batteries use nickel, cobalt, and manganese for their positive electrodes, while others use nickel, cobalt, and aluminum. Ternary lithium batteries have better low-temperature performance and higher energy density than lithium iron phosphate batteries, but their safety is not as good as that of lithium iron phosphate batteries. Lithium iron phosphate batteries: Lithium iron phosphate batteries will only burn at 800 degrees Celsius, while ternary lithium batteries will burn at 200 degrees Celsius. Therefore, most pure electric buses use lithium iron phosphate batteries.
The anode of lithium iron phosphate batteries primarily uses graphite material. This carbon-based structure resembles stacked layers of drawers, facilitating the shuttling of lithium ions during charging and discharging. I often help friends review battery specifications and have found that graphite is chosen mainly for its stability and affordability—its capacity remains steady around 372mAh/g, with a cost of just a few thousand yuan per ton, making it far more economical than expensive silicon-based materials. Additionally, graphite's conductivity is exceptionally reliable. When paired with a lithium iron phosphate cathode, it enables the battery to easily surpass 2,000 cycles while maintaining performance even in low-temperature environments without sudden failures. However, it's worth noting that some fast-charging vehicle models may incorporate around 5% silicon material to boost capacity, though this increases costs. Overall, the graphite anode is like the workhorse of the battery—safe and durable.
