Lithium-Ion batteries
2021 NOV 30
Preliminary >
Science and Technology > Energy > Innovation and New technologies
Why in news?
- A fabrication lab for Lithium-Ion batteries will soon be set up in Bangalore in an attempt to boost up-scaling and commercialisation of the technology.
About lithium-ion battery:
- A lithium-ion battery is a family of rechargeable battery types in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging.
- Li-ion batteries have a high energy density, no memory effect and low self-discharge.
Components:
- Anode, cathode, electrolyte and separator are the main components of a lithium-ion (rechargeable) battery.
- The two electrodes are immersed in the electrolyte and are separated by the separator.
- The anode is usually made up of graphite (carbon).
- Carbon graphite has a layered structure that can store the lithium ions in between its layers.
- The cathode is made up of a combination of lithium-cobalt.
- Lithium is unstable in the element form; hence the combination lithium-cobalt oxide is used for the cathode.
- Cathode plays an important role in determining the energy density of a Li-ion battery.
- The higher amount of lithium, bigger the capacity.
How it works?
- Both electrodes in a li-ion battery can intercalate or ‘absorb’ lithium ions.
- When the battery is being charged, lithium ions are absorbed (stored) in the anode.
- During discharge, lithium ions naturally flow back to the cathode through the electrolyte.
- This creates free electrons in the anode which move along the wire generating electricity.
- The process (to and fro movement of lithium-ion) repeats with each charge and discharge cycles.
- Electrolyte (lithium salt) enables the movement of lithium ions between the electrodes.
- The separator functions as a physical barrier keeping cathode and anode apart.
- It prevents the direct flow of electrons and lets only the ions pass through.
- While the cathode determines the performance of a battery, electrolyte and separator determine its safety.
- Permeable polymer membranes such as polyethylene (PE) and polypropylene (PP) are used as separators.
Why lithium?
- Lithium is the lightest metal and a powerful reducing agent (willing to donate its electrons).
- Lithium-ion batteries capitalize on the strong reducing potential of lithium ions to power the redox reaction — reduction at the cathode, oxidation at the anode.
Applications
- Lithium-ion batteries have become very commonplace: from everyday electronic products such as cell phones to electric vehicles.
- They have applications in electronic gadgets, tele-communication, aerospace, industrial applications etc.
Disadvantages of Li-ion Batteries:
- Long charging times.
- Safety issues as instances of batteries catching fires have been there.
- Expensive to manufacture.
- While the Li-ion batteries are seen as sufficiently efficient for applications such as phones and laptops, in case of EVs, these cells still lack the range that would make them a viable alternative to internal combustion engines.
Lithium in India:
- India does not have enough lithium reserves for manufacturing lithium-ion batteries
- China controls most of the lithium supply across the world.
Add ons:
- John B Goodenough, M Stanley Whittingham from the US and Akira Yoshino from Japan won the Nobel Prize in Chemistry 2019 “for the development of rechargeable lithium-ion batteries”.
PRELIMS QUESTION
With reference to ‘lithium-ion battery’,consider the following statements:
1. It is a type of rechargeable battery
2. They have no memory effect and have low self-discharge
3. They contain flammable electrolytes
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1,2 and 3
Answer