Lithium-ion battery
A lithium-ion battery or Li-ion battery is a type of rechargeable battery in which lithium ions move from the negative electrode through an electrolyte to the positive electrode during discharge, and back when charging. Li-ion batteries use an intercalated lithium compound as the material at the positive electrode and typically graphite at the negative electrode.
Li-ion batteries have a high energy density, no memory effect[1] and low self-discharge. Cells can be manufactured to either prioritize energy or power density.[2] They can however be a safety hazard since they contain flammable electrolytes, and if damaged or incorrectly charged can lead to explosions and fires. Samsung was forced to recall Galaxy Note 7 handsets following lithium-ion fires, and there have been several incidents involving batteries on Boeing 787s.
History
The lithium battery was proposed by British chemist M. Stanley Whittingham. Whittingham started on the research that led to his breakthrough at Stanford University. Early in the 1970s, he discovered how to store lithium ions within the layers of a disulfide material. After getting hired by Exxon, he improved on this innovation.[3]
Batteries with metallic lithium electrodes presented safety issues, as lithium metal reacts with water, releasing flammable hydrogen gas.[4] Consequently, research moved to develop batteries in which, instead of metallic lithium, only lithium compounds are present, being capable of accepting and releasing lithium ions.
Design
Generally, the negative electrode of a conventional lithium-ion cell is made from carbon. The positive electrode is typically a metal oxide. The electrolyte is a lithium salt in an organic solvent. The electrochemical roles of the electrodes reverse between anode and cathode, depending on the direction of current flow through the cell.
The most common commercially used anode is graphite, which in its fully lithiated state of LiC6 correlates to a maximal capacity of 372 mAh/g.[5] The positive electrode is generally one of three materials: a layered oxide, a polyanion or a spinel. Recently, graphene-containing electrodes (based on 2D and 3D structures of graphene) have also been used as components of electrodes for lithium batteries.- ↑ Memory effect now also found in lithium-ion batteries
- ↑ Design Strategies for High Power vs. High Energy Lithium Ion Cells
- ↑ Electrical Energy Storage and Intercalation Chemistry
- ↑ BSLBATT LiFePO4 Batteries for Material Handling Industry
- ↑ Polymer-Derived SiOC Integrated As a Highly Stable Li-Ion Battery
