Showing posts with label lithium ion. Show all posts
Showing posts with label lithium ion. Show all posts

Thursday, 22 February 2018

Stop Worrying About Lithium, Start Worrying about Cobalt



How the Energy Transition is Critically Dependent on a Failing State in Africa


I recently wrote a blog about how much Lithium we might need to make all the batteries to electrify transport, and whether we might run out of the stuff.  It's natural that people focus on Lithium - after all, the favoured battery technology is called "Lithium-ion", but  it turns out that Cobalt is a much greater concern.

Cobalt is a crucial element of many types of Lithium-ion battery cathodes.  The first Lithium-ion battery was commercialised by Sony and the cathode was based on Lithium Cobalt Oxide (LCO).  This type of battery is still widely used in electronic devices.

One of the most common types of Lithium ion battery for electric powertrain applications and power storage is the NCA lithium ion battery which contains lithium oxide in combination with nickel, cobalt and aluminium in the cathode together with a graphite anode.  This type of battery has higher specific energy.  Different manufacturers have their own 'recipes' but typical proportions for the cathode are:

Li(Ni 0.85, Co 0.1, Al 0.05)O2

Cobalt has atomic weight of 59 (compared to Lithium at 7), so although cobalt is present in the ratio of 1/10 the number of atoms in the battery, you need a similar mass of Cobalt as Lithium in the battery - around 600g of Cobalt for every kg of Lithium.

In my previous blog, we estimated the quantity of Lithium to electrify the world's fleet of passenger cars as 13.2 million tonnes, which would imply that there's a requirement of 7.8 million tonnes of Cobalt to achieve the same goal.

How Much Cobalt?


The United States Geographical Survey (USGS) estimates the world reserves of Cobalt at 7.1 million tonnes.  The situation is similar to that of Lithium in that identified reserves of Cobalt are about the same size as the amount needed to electrify the whole world fleet of cars.  Just like for Lithium, it is likely that once there's a strong demand for the material, exploration will result in the identification of other locations and technological development will convert known resources into exploitable reserves.

Unlike Lithium though, take a look at where in the world Cobalt is found.



Lithium is spread around politically stable countries such as Chile and Australia.  By contrast, half of the world's identified Cobalt reserves and more than half of global production comes from The Democratic Republic of the Congo (DRC).

This mineral-rich central african country has suffered almost continuous conflicts since 1996, including civil war, invasion and spillover from conflicts in adjacent countries such as Rwanda.  Largely unreported in the West, the situation is desperate with estimates ranging from 1m to 5.5m dying as a result of the wars and associated famine and disease in the last twenty years.  Foreign businesses have curtailed operations due to uncertainty, lack of infrastructure, corruption, inflation and the uncertain legal framework.

The latest news is not good.  Joseph Kaliba, the country's President since his father was assassinated in 2001 finished his last term in 2016, but still clings to power.  Currently 10 of the 26 provinces in the country are suffering from civil war.

Add a proposed new law that could increase government royalties on 'strategic' minerals such as Cobalt to levels as high as 10% and concerns about child labour and human rights abuses in Cobalt mines in DRC, and the outlook is extremely troubling.


Assault and Battery


So what does this mean for battery storage and electric vehicles?  Well, war, bloodshed and chaos doesn't always mean that the product doesn't get out of the ground, after all, bullets, guns and general carnage has to be financed somehow.  Whichever warlord is currently in charge of the area where the mines are will likely as not keep the Cobalt coming for a world hungry for battery storage.  Whether the world can turn a blind eye to batteries financing war is another matter.

However, emerging battery chemistries may reduce the need for Cobalt, and new sources may come on line as demand and prices rise, but these are not quick fixes.  In the short term we must hope that DRC avoids the worst.

So, if you are ever asked "is there enough Lithium in the world for all these electric cars and batteries?" the correct answer is "Sure thing,  but don't ask about Cobalt."

Thursday, 28 December 2017

Battery Storage Blues?

Evaporation ponds concentrate Lithium salts for extraction


Could a Shortage of Lithium Hold Back the Market for Renewables?


Energy storage is increasingly seen as critical to the decarbonisation of transportation and the means to propel the integration of clean renewable energy into the energy supply system.  In this vision of our low carbon future, we all drive in electric cars and store energy from our rooftop solar PV panels in batteries for use at home in the evening. 

The scale of the demand for batteries could be immense.

The registration of electric vehicles is growing rapidly from a very small base.  Silicon valley start up Tesla is currently going through 'production hell' trying to scale up and deliver on its ambitions (and the demand it has stimulated for its electric vehicles -EVs).  Incumbent car manufacturers are falling over one another to announce their own development plans for EVs.  In 2017 we saw announcements from Volvo that all their vehicles would be electric by 2019,    Volkswagen announced that every model would be available with an electric powertrain by 2030, and Mercedes-Benz revealed plans for their own 'gigafactory' to rival that of Tesla.

Politicians and governments have  shown similar enthusiasm for electric vehicles.  The UK government announced that it will mandate that no new cars will run on petrol or diesel by 2040.  France has announced the same goal.

The lithium ion battery is without dispute the technology of choice for applications that are both stationary (home energy storage) and mobile (electric cars and trucks), and for good reason.  Lithium ion batteries have an exceptionally high specific energy (kWh/kg) and energy density (kWh/m3) compared to other battery chemistries, which are both useful attributes for mobile applications.  The technology also scores well for lifetime - the number of times it can be charged and discharged before the capacity falls away, and power output - how fast you can get the energy out of the battery.

So in discussing the emergence of the lower cost, mass produced batteries that will be needed to usher in this new age, one question comes up again and again.  Will the world have enough lithium for all these batteries?


Lithium ion is currently the battery technology to beat


How Much Lithium Do We Need?


The good news is that it turns out that lithium ion batteries are deceptively named. 

It's called a lithium ion battery because lithium ions are the charge carriers that migrate from the cathode to the anode as current is drawn from the battery.  In fact, lithium is the smallest component of a lithium ion battery chemistry.  One of the most common formats is called the NCA lithium ion battery and contains lithium oxide in combination with nickel, cobalt and aluminium in the cathode together with a graphite anode.  Typical proportions for the cathode are:

Li(Ni 0.85, Co 0.1, Al 0.05)O2

Because lithium is such a light element (atomic weight 7), it works out to be only 7% of the cathode weight, so let's estimate around 2% of the weight of the entire cell, including the anode, electrolyte and packaging.

The Tesla Model S uses 18650 format cells assembled into 5.3kWh packs of 444 cells (see this 'teardown video'), making each cell 12Wh.  With 18650 format cells weighing in at around 45g each an 80kWh battery pack for a car would require 6,666 cells weighing a total of 300kg.  2% of 300kg is 15kg of lithium per vehicle.

With annual car sales at around 80m per year, a transition to a future where every single new car was fully electric would require 1.2 million tonnes of lithium each year.


At the rate of 80m new cars a year, it would take 11 years to replace the entire world fleet of cars, which is estimated to comprise around 900 million vehicles.  Lithium can be recovered from used batteries and recycled to make new ones, so in theory once the whole fleet is replaced then no more would need to be extracted.  So the total lithium requirement to move to fully electric cars would be 13.2 million tonnes.

Is there Enough Lithium?


Lithium is the 25th most abundant element in the Earth's crust and is also present in seawater.  It has been estimated that there is 230 billion tonnes of Lithium in the oceans.  The challenge is that it tends to be found in low concentrations. 

Lithium is found in highest concentrations in underwater reservoirs of brine, and in hard granitic rocks.  In Chile, brine is pumped up from the underground pools into vast  ponds (see image at top) where the water evaporates until the water is rich in Lithium Chloride, which can be precipitated out by reaction with sodium carbonate to create insoluble Lithium Carbonate. 

In Australia the mineral Spodumene is mined for Lithium.  The rock is crushed and heated in a kiln, then mixed with sulphuric acid and roasted again to produce Lithium Sulphate.

Pure Lithium is then extracted by the salts by electrolysis.


Lithium is available from many sources



The United States Geological Survey (USGS) estimates the world proven reserves as 14 million tonnes of lithium, distributed as shown in the chart.  While this figure is similar in scale to the requirement for electrification of vehicles, which leaves little extra for stationary applications and consumer electronics, there's good reason to believe that we have enough lithium:

  • Reserves represent only those resources that have been discovered so far, and that are judged to be capable of economic extraction with current approaches.  The easily extracted crude oil was the first to be exploited, but as demand increased, reserves were discovered in more and more places and technologies capable of their economic extraction from difficult locations (such as under the the North Sea) were developed. It is likely that the same will occur as demand for lithium rises.  USGS currently estimates total resources at 35 million tonnes. 
  • Lithium is already found in numerous locations around the globe (see chart), including many countries that could be judged to be politically stable.
  • As the commercial importance of energy storage increases and the scale of the financial opportunity from battery storage becomes evident to investors, funding will pour in and this will accelerate the development of new battery chemistries that use other materials.   For example, Gridential, a company that claims to have given old lead-acid battery technology a revamp with silicon wafer technology adapted from the solar industry, recently received $11m in two financing rounds.

However, having enough Lithium in the ground is not the same as being able to get it out fast enough to keep up with demand.

USGS estimates that world production rate for lithium at 36,000 tonnes per year.  It takes around seven years to bring new brine extraction capacity on stream and three to four for extraction from hard deposits.  It is highly conceivable that there will be capacity crunches along the way and a scramble by automobile manufacturers to secure supplies, but in answer to the question of whether there is enough lithium for the electrification of transport - it looks like yes, there is.

 Cobalt, another essential ingredient of lithium ion batteries, on the other hand, that's a completely different story...and one for another blog.