In addition to traditional lithium batteries, solid-state batteries and water-based lithium-ion batteries have also set off a research boom. Among them, high energy density and high safety are the two key factors in battery research. How to improve energy density on the basis of ensuring safety is the common pursuit of academia and industry.

　　A common lithium battery generally includes a positive electrode material, a negative electrode material, an electrolyte, a separator, and a battery casing. The positive electrode, negative electrode and electrolyte are all key parts of a battery.

　　The cathode material is a key link in limiting the energy density of lithium-ion batteries. Simply put, as a whole system, the energy density of the battery is related to the positive electrode, the negative electrode, and the electrolyte, and the positive electrode material is the shortcoming of the three.

　　For lithium-ion batteries, the current common practice is to use transition metal oxides as cathode materials. This transition metal oxide usually has a layered structure or a structure with pores, which can ensure that the structure will not collapse during the process of allowing lithium ions to enter and exit freely. But the problem is that the metal oxide framework itself is very heavy, and this part itself cannot provide capacity, which reduces the energy density of the battery in a disguised form.

　　For the future development of lithium batteries, the current organic system has developed to an obvious bottleneck stage, that is, it is difficult to ensure good safety when increasing energy density. Therefore, while improving energy density, not losing safety is an inevitable direction for battery research.

　　These two directions have great prospects and hopes, but also have their own problems that need to be solved.

　　Lithium-ion battery (LIB) has become the main energy storage solution in modern social life. Among them, lithium iron phosphate batteries are a perfect substitute for lead-acid batteries and are the first choice in the energy storage industry.