Lithium-ion batteries are generally harmless to humans and the environment during normal use. However, improper disposal of discarded lithium-ion batteries can harm the environment and then affect surrounding organisms and humans through environmental transmission. This is mainly because the chemicals contained in lithium-ion batteries, such as lithium hexafluorophosphate and polypropylene glycol, can cause organic pollution. Additionally, the heavy metals they contain, such as cobalt, can also harm the environment.
In the treatment of waste lithium-ion batteries, the first step is to pre-treat them, including discharging, dismantling, crushing, and sorting. The plastic and iron shells after dismantling can be recycled. Then, the electrode materials are subjected to alkaline leaching, acid leaching, and other processes before extraction.
The electrolytes and their conversion products from used lithium-ion batteries, such as LiPF6, LiAsF6, LiCF3SO3, HF, P2O1, etc., as well as the solvents and their decomposition and hydrolysis products, such as DME, methanol, formic acid, etc., are all toxic and harmful substances. Used lithium-ion batteries should be sent to qualified facilities for unified treatment and should not be discarded at will.
Lithium-ion batteries contain various toxic substances, exhibiting strong corrosiveness and polluting properties. Furthermore, waste lithium-ion battery electrolytes contain highly toxic, flammable, explosive, and corrosive electrolytes and organic solvents. Improper disposal or leakage will pollute and damage the atmosphere, water, and soil. Moreover, electrolyte leaks and excessively high temperatures can cause battery explosions and fires, directly threatening people's lives and property.
In addition, a series of pollutants are generated during the crushing, sorting, and high-temperature pyrolysis pretreatment of waste lithium-ion batteries, such as electrolyte decomposition, plastic film pyrolysis, crushing dust, and waste residue. These pollutants not only cause serious pollution to the atmosphere and water bodies but also have a severe corrosive effect on equipment. At the same time, the various acid and alkali leaching agents, extractants, and active additives added during the process not only increase the cost of the recycling process, causing resource waste and increased energy consumption, but also generate a large amount of wastewater, waste gas, waste residue, and waste additives, which cause secondary pollution.
