Polyanionic cathode materials have obvious advantages and disadvantages, and the pace of industrialization is accelerating

Polyanionic cathode materials are currently one of the three major technical routes for sodium-ion batteries (the other two major technical routes are layered oxides and Prussian blue compounds). Polyanionic compounds are a type of compound containing tetrahedral or octahedral anionic structural units. They have a special crystal phase structure and have outstanding properties when used as cathode materials.

The chemical formula of the polyanionic cathode material is NaxMy(XO4)n, where M is a transition metal such as Fe, Mn, Ni, Cu, V, etc., and X is S, P, Si, Mo, As, etc. Polyanionic cathode materials have outstanding advantages of long cycle life, with the number of charge and discharge cycles reaching 5,000. In addition, they also have good rate performance, high operating voltage, good stability, high safety, and wide operating temperature range (-40 degrees to 55 degrees Celsius). degree) and other advantages.

Polyanionic cathode materials mainly include two categories: transition metal phosphate series and transition metal sulfate series. The transition metal phosphate series has poor performance and is hindered from large-scale application. Vanadium (V) can be used to improve performance, but vanadium is costly and toxic. In comparison, the transition metal sulfate series has advantages in performance, cost, etc., and is the mainstream route for polyanionic cathode materials.

According to the “In-depth Market Research and Development Prospects Forecast Report on China’s Polyanionic Cathode Material Industry from 2023 to 2028” released by the Industrial Research Center It shows that at present, the representative sulfate polyanion cathode material is Na2Fe2(SO4)3, which has the advantages of high voltage, large specific capacity, high thermal stability, etc., and the raw materials are easily available, easy to synthesize, and low cost. It is the cathode material for sodium batteries. One of the best solutions.

Cathode material is one of the core components of sodium-ion batteries. In the cost of sodium-ion batteries, cathode materials account for more than 25%. Therefore, the number of companies in my country entering the market layout of cathode materials for sodium batteries is increasing. Since the three major lithium battery cathode material technical routes each have their own advantages and disadvantages, multiple technical routes currently coexist in our country’s market. With the advantages of better performance and lower cost, sulfate polyanion cathode materials have attracted many companies such as Penghui Energy, Chuanyi Technology, and Zhongna Energy to enter the market.

The preparation process of polyanionic cathode materials is close to that of lithium iron phosphate cathode materials, and it is easy to realize industrialization. Its economic advantages will be further improved after large-scale mass production, and it is expected to increase market penetration. Polyanionic cathode materials also have some shortcomings. Their conductivity is poor, and methods such as carbon coating and doping are required to modify the materials. Modification is difficult and will reduce energy density.

Industry analysts said that in comparison, in my country’s sodium battery cathode material market, layered oxide cathode materials have excellent overall performance , the technical process is easy to realize, the largest number of enterprises are deployed, and it is the first to realize industrialization. The industrialization development of polyanionic cathode materials is slower than that of layered oxide cathode materials, but its technology and processes are constantly making breakthroughs, and the pace of practical application will accelerate. It is expected to achieve industrialization after layered oxide cathode materials.