The cathode precursor, like the nmc precursor of a lithium-ion battery, is a material at the final step before becoming a cathode, or an ingredient from which a cathode is formed.
The most used method for producing cathode precursors is co-precipitation, a process in which a substance carries down other substances along with it. As the name suggests, it is the simultaneous precipitation of different ions in aqueous or nonaqueous solutions.
To take the example of an NCM cathode precursor, the first step to make it is to dissolve nickel, cobalt, and manganese to make a metal solution. When the complexing agent and ph adjuster are mixed into the solution and stirred, reaction and flocculation take place, inducing precipitation. The last is to wash and dry the precipitated substances. Below will explain it more specifically about the cathode precursor manufacturing process,
Making the ingredients solution （flow chart )
1.1 Process preparation:
(1) Wear dust masks, goggles, rubber gloves, hard hats, etc.;
(2) Check whether the relevant pipelines, valves and pumps are normal.
1.2 Calculation and making the ingredients solution
(1) Obtain the target concentration of ingredients according to the provided process documents.
(2) Determine the volume of the dosing solution, and calculate the required sulfate crystals according
to the volume and the target concentration of nickel, cobalt, and manganese. (The calculation method
is as follows).
1.3 Calculation method of ingredients precursor If you want to make Ni82Co12Mn6(OH)2, then calculate the target concentration of nickel, cobalt and manganese, calculate the total content of each metal required in a tank of solution, also need to calculate the metal feed if not enough for the initial solution after testing the materials.
2. Reacting process(co-precipitation process)
2.1 Schematic diagram of the chemical reactor equipment connection
2.2 Operating procedures In this process includes preparations (Check whether the liquid level of the balance tank is within the allowable range, whether the pipeline from the bottom valve to the reactor is unobstructed, whether the damper and safety valve back pressure valve are normal, whether the inside of the chemical reactor for cathode precursor synthesis is clean, whether the bottom valve of the reactor is closed, etc.). Add the first liquid to the reactor, turn on the stirring and heat up, add ammonia, add qualified metal solution, and alkali solution addition. Measure the concentration of dissociated ammonia in the reactor, particle size measurement in the reactor, electron microscope, specific table and tap density test in the reactor. When product production is completed and meets your target parameters, it is necessary to stop and discharge the material.
3. Washing After the reaction is completed, the reaction slurry flows into the aging tank. When the aging tank reaches 80% capacity, start discharging it to the washing machine. When the aging tank has 20% capacity left, stop discharging, and handling it like this repeatedly. During the washing process, we recommend using dilute alkali and hot water.
4. Screening and packaging of the dried materials
After washing, the material is transported to the dryer, and the temperature is set at 130±10°C to ensure that the material is dried. After drying, it passes through the iron remover. It is best to control the magnetic foreign matter in the dryer with MI≤80 ppb. After drying the material, then sieves through a 400-mesh sieve, and then uses electromagnetic iron removal to ensure that the magnetic foreign matter MI is less than or equal to 50 ppb. In the last step, after the full analysis and testing, the qualified products can be affixed confirming labels and move to packaging step, and the unqualified label can be affixed
non-conforming label for rework.