Lithium-ion batteries are harmful to the human body.
The most harmful thing is the electrolyte solution. The electrolyte is a volatile organic liquid and is obviously corrosive. Long-term inhalation of volatile gases can cause damage to the respiratory tract. Cause respiratory illness.
Lithium-ion batteries emit some radiation because they contain cadmium, which can cause osteoporosis.
The work environment can contain many harmful elements. Some mercury elements are relatively common, and there are other lead elements. Causes heavy metal-related illnesses.
Like all chemical batteries, lithium-ion batteries are made up of three parts: a positive electrode, a negative electrode and an electrolyte. The electrode materials are all lithium ions which can be intercalated (inserted)/deintercalated (deintercalated).
Solution lithium-ion battery electrolytic
Solute: Lithium salts are often used, such as lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), and lithium tetrafluoroborate (LiBF4) . Solvent: Since the operating voltage of the battery is much higher than the decomposition voltage of water, lithium-ion batteries often use organic solvents, such as ether, ethylene carbonate, carbonate propylene, diethyl carbonate, etc.
Organic solvents often destroy the structure of graphite during charging, causing it to delaminate and form a solid electrolytic interphase (SEI) on its surface, leading to passivation of the electrodes. Organic solvents also pose safety concerns such as flammability and explosiveness.
The positive electrode materials of lithium batteries include lithium cobalt oxide LiCoO2, a materialu ternary Ni+Mn+Co, lithium manganate LiMn2O4 as well as a conductive agent and an adhesive, which are coated on an aluminum foil to form a positive electrode, and the negative electrode is layered with graphite plus a conductive agent and an adhesive are coated on the copper foil base tape. So far, the most advanced negative electrode layered graphite particles have adopted nanocarbon.
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The role of battery electrolyte< /h3>< p>
The composition of lithium battery electrolyte is shown as follows.
1. Ethylene carbonate: molecular formula C3H4O3.
Transparent colorless liquid (>35℃), crystalline solid at room temperature. Boiling point: 248℃/760mmHg, 243-244℃/740mmHg; Point of ecair: 160℃; Density: 1.3218; Refractive index: 1.4158 (50℃); solvent.
2. Propylene carbonate: molecular formula C4H6O3.
Colorless and odorless transparent liquid, or light **, soluble in water and carbon tetrachloride, mixed with ethanolMiscible with ether, acetone, benzene, etc. It is an excellent polar solvent. This product is mainly used in polymer operations, gas separation processes and electrochemistry. It is especially used to absorb carbon dioxide from natural gas raw materials and synthetic ammonia in petrochemical plants. It can also be used as plasticizer, spinning solvent, olefin and aromatic hydrocarbon extractant, etc.
This product should be stored in a cool, ventilated, dry place away from sources of fire, and should be stored and transported in accordance with general regulations for chemical products.weakly toxic ics.
3. Diethyl carbonate: molecular formula CH3OCOOCH3.
Colorless liquid with a slight odor; vapor pressure 1.33kPa/23.8℃; flash point 25℃ (flammable liquid may volatilize into vapor and flow into the air. As the temperature increases, volatilization accelerates. When volatilization when a mixture of vapor and d Air can spark when it comes into contact with a fire source. This brief combustion process is called flash combustion, and the lowest temperature at which flash combustion occurs is called the flash point. 43°C; boiling point 125.8°C; solubility: insoluble in water, miscible in most organic solvents such as alcohols, ketones and esters; ; stability: stable; hazard mark 7 (flammable liquid); used as a solvent and used in synthesis;e organic
Electrolyte for lithium batteries
In automobile batteries, electrolysis. The liquid mainly plays the role of electrochemical reaction and conduction, as follows: 1. Electrochemical reaction Only the presence of electrolyte can cause the battery to discharge normally, because the electrode plate releases electrical energy by absorbing the sulfuric acid in the electrolyte 2. . Conduction by electrolysis. The liquid can form a current loop in the battery, allowing current to charge and discharge in the battery. About lithium battery electrolyte: Lithium battery electrolyte is the carrier of ion transmission in lithium batteries. salts and organic solvents. , Maintenance-free batteries do not need to add electrolyte at a later stage. If the maintenance-free battery feels that energy is not used, you can add electrolyteappropriately. keep the battery stationary for about 6 hours until the electrolyte temperature is below 35 degrees Celsius. To charge the battery
The electrolyte in lithium batteries is an important component of the battery and has a great impact on it. Battery performance. In traditional batteries, the electrolyte uses water as the liquid system. However, since the theoretical voltage for water decomposition is only 1.23 V, even taking into account the overpotential of hydrogen or oxygen, the maximum voltage is reached. the battery with water as the solvent electrolyte system is only about 2V (like a lead acid battery). The battery voltage reaches 3~4V. The traditional aqueous solution system is obviously no longer suitable for the needs of the battery. Instead, a non-aqueous electrolyte system should be used as the electrolyte for lithium-i batterieswe. The electrolyte for lithium batteries is primarily organic and can withstand high voltages without breaking down.
The electrolyte used. in lithium-ion batteries is an ionic conductor with a lithium salt electrolyte dissolved in an organic solvent. Generally, the organic electrolyte used in practical lithium-ion batteries should have the following properties:
p>(1) The. ionic conductivity is high, generally it should reach 10-3~2*10-3S/cm; the migration number of lithium ions should be close to 1;
(2) The potential range of electrochemical stability is wide; there should be an electrochemical stability window of 0~5V;
(3) Good thermal stability, wide operating temperature range;
(4) Stable chemical properties, no chemical reaction with current collectors and chemicals in the battery
(5) is safe, low toxic and ofpreferably biodegradable.
Suitable solvents should have a high dielectric constant and low viscosity. Commonly used solvents include alkyl carbonates such as PC and EC, which are highly polar and have a high dielectric constant, but have high viscosity and intermolecular forces. , lithium ions move slowly there. Linear esters, such as DMC (dimethyl carbonate) and DEC (diethyl carbonate), have a low viscosity but also a low dielectric constant. Therefore, in order to obtain a solution with high ionic conductivity, they are generally used PC+DEC, EC+DMC. and other mixed solvents. These organic solvents have some odor, but generally speaking, they can meet EU RoHS and REACH requirements. They are very toxic, environmentally friendly and environmentally friendly materials.
Anionic conductor saltss currently developed inorganic compounds mainly include three categories: LiBF4, LiPF6 and LiAsF6. Their electrical conductivity, thermal stability and resistance to oxidation are in the order:
Conductivity: LiAsF6≥LiPF6. >LiClO4>LiBF4
Thermal stability: LiAsF6>LiBF4>LiPF6
Oxidation resistance: LiAsF6≥LiPF6≥LiBF4>LiClO4
LiAsF6 has conductivity and very high stability and charge and discharge rates of batteries, but its application is limited due to arsenic toxicity. Currently, LiPF6 is most commonly used.
All materials of currently commonly used lithium batteries, including electrolytes, comply with EU RoHS and REACH requirements and are environmentally friendly energy storage products.