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Principle
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- Lithium, as you can see in the table above, has the highest electrochemical potential.
- It wants to lose electrons readily which makes it very reactive. That’s why you don’t get lithium in free form.
- However, when mixed with metal oxide lithium sits very stably.
- Thus, if we use this ability of lithium to be very unstable by itself to becoming very stable in metal oxide, we can derive electricity. This is what happens in a Li-ion battery
Working of a Li-ion Battery
- Lithium is mixed in metal oxide (typically cobalt, nickel, or manganese)) is used as cathode.
- Graphite is use as a place to hold Li-ions which becomes an anode.
- As we have seen Lithium in metal oxide is very stable.
- In Li-ion battery we separate Lithium from metal oxide by pulling out its constituent electrons and ion forcefully by applying energy.
- The electrons and ions of Lithium are then given separate paths namely a metallic wire and an electrolyte.
- This is called charging as it required external energy to separate electrons and Li-ions from Lithium metal oxide.
- The li-ions moving through electrolyte and electrons moving through the wire then recombine at anode which is graphite.
- Once all the electrons and ions are pulled out the battery is completely charged.
- The lithium ions and electrons that is sitting between graphite sheets are unstable and wants to go back to metal oxide. If we again give separate paths to electrons and ions we can derive electricity.
- Thus Li-ion battery is used to store energy by shuttling lithium ions back and forth between the anode(Li-ion in graphite) and cathode(Lithium in metal oxide).
Advantage of Li-ion Batteries
- Light weight
- Lithium being lightest metal.
- High Energy Density
- Lithium having highest electrochemical potential has very high energy density.
- A typical automobile lead-acid battery weighs 6 kilograms more to store the same amount of energy than a lithium-ion battery.
- In consumer electronics like mobile, laptops, camera etc I kilogram of Nickle cadmium batteries stores typically 60 to 70 watt-hours.
- A typical lithium-ion battery can store 150 watt-hours of electricity in 1 kilogram of battery.
- Minimum losses
- A lithium-ion battery pack loses only about 5 percent of its charge per month, compared to a 20 percent loss per month for Ni-Cd batteries.
- Low Maintenance
- Lithium-ion batteries can handle hundreds of charge/discharge cycles.
Disadvantages
- Faster discharge
- While quick discharge is an advantage in electric vehicle and consumer electronics applications, it is not suitable to store energy for longer than 4 hours.
- Thus, it is not suitable for grid-level storage which is necessary for renewable energy like solar which suffer from intermittency problem.
- Ageing
- Li-ion batteries suffer from ageing at room temperature. Therefore, in a consumer electronic, batteries need to be partially charged for longer life.
- Transportation
- Another disadvantage of li-ion batteries is that there can be certain restrictions placed on their transportation, especially by air to protect against short circuits.
- Cost
- Lithium-ion batteries are around 40% more costly to manufacture than Nickel cadmium cells owing to high cost of lithium refining, cobalt and nickel.
- Lithium reserve (Optional)
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Lithium Reserves
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- Lithium is currently produced from hard rock or brine mines.
- Australia is the world’s biggest supplier, with production from hard rock mines.
- Argentina, Chile and China are mainly producing it from salt lakes.
- Chile, Argentina and Bolivia (Lithium triangle) in South America is believed to account for more than 50% of the world’s proven Lithium reserves.
Lithium reserves in India
- The ancient igneous rock deposits in the Karnataka’s Mandya district holds the first traces of Lithium ever to be discovered in India. But it is merely 1,600 tonnes.
- But in a big development, recently 5.9 million tonnes of lithium reserves found for the 1st time in Jammu and Kashmir.
- India currently imports all of its lithium batteries.
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India’s steps
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- In March 2019, India signed a MoU with Bolivia to explore and extract Lithium.
- India has also signed bilateral agreement with Argentina for securing strategic minerals, which will be operationalized via KABIL’s contract with three state-owned organizations in Argentina.
- India and the US are also looking at setting up an alternative supply chain for lithium. o KABIL is also exploring the direct purchase of cobalt and lithium.
- Lithium plant: India’s first Lithium plant has been set up at Gujarat in 2021, where a private company has planned investment of Rs 1000 crore to set up a refinery. The refinery will use Lithium ore to produce base battery material.
KABIL
- A PSU to ensure a consistent supply of critical and strategic minerals to Indian domestic market.
- It would carry out identification, acquisition, exploration, development, mining and processing of strategic minerals overseas.
- India has also signed Critical Mineral Investment Partnership with Australia primarily for supply of lithium and cobalt.
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China’s Dominance
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- China contributes to 60% of global production of rare earth elements.
- China’s share of refining is around 35% for nickel, 50-70% for lithium and cobalt, and nearly 90% for rare earth elements.
- China has a huge head start on India in terms of securing lithium deposits.
- Around 3/4th of battery cell manufacturing capacity is in China,
- China has heavily invested in mines of both Australia and Latin America to ensure an overall command of lithium supply chain.
- It also controls cobalt mines in the Democratic Republic of Congo, from where 70% of this mineral is sourced.
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Alternatives
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Sodium-Sulphur
Advantage
- Sodium-Sulphur can be recharged 4500 times compared to 500 times of Lead-acid and Li-ion batteries.
- Further Lithium is way more costly than sodium. 10 times more per kilo.
Limitation
- Problem is Sodium used in these batteries need to be in liquid state and that happens at high temperatures of 350 degree Celsius. So, Sodium-Sulphur cannot be used in laptops and mobile phones.
- Price per charge-discharge cycles is high.
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Microbial fuel cell
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- It uses an organic electrolyte instead of inorganic ones in the above case.
- In other words, anaerobic oxidation of organic substances such as acetate, glucose, lactate, ethanol by microbes.
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