3 Easy Steps to Recycling Lithium Batteries

Lithium-ion battery technology is quickly becoming a standard in many sectors, resulting in an exponential rise in production and sales and necessitating the need for Recycling Lithium Batteries. Because lithium-ion batteries have a limited service life of around 5 to 8 years, there will be an enormous increase in waste lithium-ion batteries as the technology matures.

The technical and safety necessities for lithium battery recycling are becoming more stringent, and the management and resolution of cost and safety hazards in the recycling process is a key topic in the creation of lithium batteries today.

Is there a recycling value of lithium batteries?

Lithium batteries, which are composed of about 15 percent cobalt, 25 percent iron, 0.1 percent lithium, 14 percent copper, and 4.7 percent aluminum, have a high recycling value. According to market projections, the average revenue per ton of cathode scrap cobalt-lithium film is $9000.

Because high value-added metals like lithium, cobalt, nickel, and so on are generally found in used lithium-ion batteries' cathode materials, the majority of current studies on recycling lithium-ion batteries focus on Cathode Materials.

As a result, the recycling procedure for used Li-Ion batteries is usually known as the separation, purification, and re-utilization of valuable metal components in cathode materials.

The chemical composition of a lithium-ion battery includes a large amount of lithium copper, manganese, cobalt, and other metals as well as lithium polyvinylidene fluoride hexafluorophosphate, and other hazardous toxic chemicals. The importance of resource recovery and safe treatment is crucial.

 The recycling steps for lithium-ion power batteries

The recycling process for lithium batteries can be broken down into three phases:

• Pretreatment
• Secondary treatment
• Deep treatment

(I) Pre-Treatment

It's been discovered that the lithium-ion battery has a residual charge after it's obsolete; therefore, when it's recycled, toxic HF is produced as a result of the moisture. As a result, the lithium battery must be pretreated to discharge its charge before recycling.

There are currently two primary treatment techniques:

1. Immersion
2. Resistance

The charge is released by sodium chloride solution in the immersion method, and to avoid the formation of harmful gases, the battery is immersed in dilute alkaline water, which has the reaction formula HF+NaOH -> NaF+H2O.  

At the same time, the positive and negative electrodes are physically separated according to the different material densities of the battery casing and separator, as well as the proportion of positive and negative electrodes.

(II) Secondary treatment

The secondary treatment is meant to remove the cathode and anode active materials from the substrate, usually utilizing heat treatment, electrolysis, and organic solvent dissolving techniques. The heat treatment technique is simple to use and has a long history of usage.

At a certain temperature, the cell is positioned, and PVDF separates as it volatilizes and decomposes. The aluminum foil melts at 600°C to 700°C as a result of the conductive additive's combustion reaction.

The secondary treatment can also be done by alkaline dissolution and organic solvent dissolution. When these chemicals come in contact with PVDF, they can dissolve it and a portion of the electrolyte at the same time.PVAF has a high sensitivity to hydrolysis, and it is unstable in water.

In general, NMP, DMF, DMAC, DMSO, and other organic solvents can be used for treatment at temperatures above 70 °C. PVAF dissolution reached the maximum degree at 211 g/L solubility 177 g/218 g/L, and 241 g/L respectively.

DMSO has the best solubility for waste lithium-ion batteries and excellent performance in terms of environmental protection, low cost, and non-toxicity, among others. When the temperature is below 65 degrees Celsius, aluminum foil produced after 90 minutes of treatment may be recycled immediately.

(III) Deep treatment

The recycling of lithium-ion batteries, which includes leaching and separation, involves lengthy procedures.

In Inorganic acid leaching, there are two distinct types of leaching:

• Microbial leaching
• Inorganic acid leaching

A. Microbial Leaching

It's more popular since it has a high rate of conversion, low cost, and is easy to do. The waste lithium-ion battery is currently recycled by autotrophic bacteria, including ferrous oxide microspirochetes, sulfur oxide-thiobacillus, and ferrous oxide thiobacillus.

The metabolic acid, through the bacterial's physiological reaction to promote growth and regeneration, may be used in the leaching procedure for spent lithium-ion power batteries.

In the study, Cu 2+ is used as a catalyst, and the leaching efficiency of Co 2+ was 99% after six days with 0.85g/L catalyst, whereas the leaching efficiency of Co 2+ was reduced to 40.3% after ten days without Cu 2+. The results demonstrate that Cu 2+ has some significant effect on the recycling efficiency of LiCoO2.

B. Inorganic acid leaching

This method is to leach the battery cathode material with inorganic acids. This includes hydrochloric acid, sulfuric acid, nitric acid, and organic acids such as oxalic acid, citric acid, and grapes acid. For example, oxalic acid is used to recycle the cobalt and lithium components in the battery. Cobalt and lithium element extraction efficiency can reach 97-98%.

After 1.5 hours of stirring with H2C2O4 at 95°C and a solid to liquid ratio of 16g/L, the solution is clear. It will be free-flowing, and colorless. The cobalt and lithium components may be leached out of the cathode material. This involves using inorganic acid during the inorganic acid treatment.

In general, inorganic acid's leaching efficiency is excellent. However, it generates a lot of hazardous and noxious gases such as sulfur dioxide and nitrogen

The final isolation and purification is largely the separation and purification of lithium, nickel, manganese, and cobalt, among others. The main methods used are solvent extraction, chemical precipitation, and electrochemical processes.

Conclusion

Lithium-ion batteries are widely used in many industries because of their high energy density. However, the recycling process of lithium-ion batteries is challenging due to the complex chemical composition of the cathode and anode materials.

In this article, we have reviewed the three main steps in recycling lithium-ion batteries. We hope that this article will provide you with some useful information on recycling lithium-ion batteries.