Batteries or batteries that have lithium as main constituent have as one of its features that they are quite light, because lithium is the least dense metal discovered to date.
To give you an idea, this silvery white metal ball in the water, because it is two times less dense than she.This is due to the fact that lithium has three protons and three neutrons.
There are two main types of lithium batteries, one of which is calledlithium-iodine. It was developed mainly for use in heart pacemakers, since it’s pretty light, safe (no releases gases because it is sealed), has a good durability (about 8 to 10 years), provides a 2.8 V voltage and a high charge density (Wh/0.8 cm3).
The electrodes are formed by lithium and iodine complex, which are separated by means of a crystalline lithium iodide layer that allows the passage of electric current. The metallic lithium acts as theanode of this stack, i.e. is the negative pole that oxidises, losing electrons. Already the cathode, the positive pole that comes down, receiving electrons, is the iodine complex .
See the semirreações that occur in the electrodes and the equation that represents the overall reaction this battery type:
Anode: 2 Li Semirreação(s) → 2 Li+(s) + 2e–
Semirreação cathode: 1 I2 (s) + 2e–→ 2 I – (s)
Overall reaction: 2 Li(s) + 1 I2 (s) → 2 LiI(s)
Lithium-iodine batteries have very small coins format, as shown in the following figure:
The other type of cell or battery is lithium ion, as howsmb says. She takes that name exactly because your operation is based on the movement of lithium ion (Li+). She is currently widely used in the batteries of mobile phonesand your potential varies between 3.0 and 3.5 V.
The anode and cathode are formed by atoms arranged in plans as if they were blades with spaces where the lithium ions. The anode is composed of graphite with copper and metal ions are inserted in the hexagonal carbon structures, forming the following substance: ReadyC6. Already the cathode is formed by intercalated lithium ions in a lamellar structure oxide (ReadxCoO2 ).
Thus, we have that the lithium ions leave the anode and migrate through a non-aqueous solvent to the cathode.
Anode: Li Semirreação y (C) 6 (s) → y Li + (C) 6 + y and-
Cathode Semirreação: LixCoO2 (s) + y Li+(s) + y and– → Readx + yCoO2 (s)
Overall Reaction: Read y (C) 6 (s) + Read x CoO 2 → (C) 6 (s) + Lix + yCoO2 (s)
These batteries are rechargeable, simply use an external electric current that causes the migration of lithium ions in reverse, i.e. for graphite oxide.