Let's look at the quality judgment criteria of electrolyte, the most well-known are moisture and HF, but here we should remind that many times, after adding special additives, when you test HF or moisture, you wll find that the result is large. This is because the substances themselves react with the reaction reagents, resulting in biased results. As we said before, there are generally two test methods for testing moisture and HF, one is to test before adding the additive, and the other is to change the non-reactive test reagent.
How to choose the electrolyte, let's take a look at this data first. With the same electrolyte, continues to increase the voltage of the LCO, and the difference in cycling performance is very obvious. In addition to the instability of the lithium-cobalt material itself under high pressure, the oxidation of the cathode is stronger under high pressure, and it is necessary to improve the electrolyte in a targeted manner.
Therefore, from the perspective of voltage and material, different voltages, different cathode and anode electrode materials, the electrolytes often have formula adjustments. Let's take a look at some ideas for improvement.
For example, for the demand for higher voltage, lithium salts, solvents, and additives have a lot of room for optimization, and there are many relevant literature reports. For example, in the case of 5V electrolyte, fluorinated solvents are required to improve oxidation resistance.
For different cathode main materials, it is also different pertinence, such as LMO, LiBOB is a commonly used manganese dissolution inhibition additive; High nickel NCM, need to increase the content of PS; The choice of additives such as SN and ODFB is helpful for the improvement of LCO high temperature cycling.
Different anodes, taking graphite as an example, artificial graphite and natural graphite use the same electrolyte, and the difference is very obvious. In fact, different materials have different cycle attenuation mechanisms, so if you want to do a good job in the overall performance of the battery, the electrolyte should be optimized in a targeted manner.
Here is a brief comparison of the differences between commercial electrolytes and university electrolytes, and there are certainly obvious differences between the two in terms of formulation expressions. In the material chemistry system, the commercial electrolyte needs to meet the overall performance of the product, so the electrolyte is relatively complex. In order to reveal some reaction rules, the formula of college electrolyte is relatively simple, but often introduced some new materials, and more attention is paid to novelty and certain performance indicators. Of course, commercial electrolytes must be developed with mass production and practical use as the goal.
