Lithium iron phosphate (LiFePO4) is particularly well-suited for power applications, hence the inclusion of the word “power” in its name, resulting in a lithium iron phosphate power battery. Some also refer to it as a “lithium iron (LiFe) power battery.” 1. Meaning: The main cathode materials currently used in lithium-ion batteries are: LiCoO2, LiMn2O4, LiNiO2, and LiFePO4. Among these metal elements, cobalt (Co) is the most expensive and has limited storage.

Lithium iron phosphate (LiFePO4) is particularly well-suited for power applications, hence the inclusion of the word “power” in its name, resulting in a lithium iron phosphate power battery. Some also refer to it as a “lithium iron (LiFe) power battery.”

1. Meaning: The main cathode materials currently used in lithium-ion batteries are: LiCoO2, LiMn2O4, LiNiO2, and LiFePO4. Among these metal elements, cobalt (Co) is the most expensive and has limited storage. Nickel (Ni) and manganese (Mn) are relatively inexpensive, while iron (Fe) is the least expensive. The prices of the cathode materials also track the prices of these metals. Therefore, lithium-ion batteries using LiFePO4 as a positive electrode material should be the cheapest. Another advantage is their environmental friendliness.

Rechargeable battery requirements include: high capacity, high output voltage, excellent charge-discharge cycle performance, stable output voltage, high current charge and discharge capability, electrochemical stability, safety during use (no combustion or explosion due to improper operation such as overcharging, overdischarging, and short-circuiting), a wide operating temperature range, low or no toxicity, and no environmental impact. Lithium iron phosphate batteries using LiFePO4 as a positive electrode excel in all these performance requirements, particularly in terms of high discharge rates (5-10C discharge), stable discharge voltage, safety (no combustion or explosion), lifespan (number of cycles), and environmental friendliness. They are currently the best high-current output power battery.

2. Structure and Operating Principle: The internal structure of a LiFePO4 battery is shown in Figure 1. On the left is the battery’s positive electrode, made of olivine-structured LiFePO4, connected to the positive electrode by aluminum foil. In the middle is a polymer separator, which separates the positive and negative electrodes, allowing lithium ions (Li+) to pass through but electrons (e-) to not. On the right is the battery’s negative electrode, made of carbon (graphite), connected to the negative electrode by copper foil. Between the upper and lower ends of the battery is the electrolyte, and the battery is sealed in a metal casing.

During charging, lithium ions (Li+) in the positive electrode migrate through the polymer separator to the negative electrode. During discharge, lithium ions (Li+) in the negative electrode migrate through the separator to the positive electrode. Lithium-ion batteries are named for this back-and-forth migration of lithium ions during charging and discharging.