Aluminium–air batteries: A solution for clean energy

As India aims to become a clean energy superpower, we need to explore and adopt technologies that are in line with this objective. Aluminium–air batteries are proving to be an intelligent and much-needed solution to transition to clean energy.

The modern-day society is currently in a transition phase from fossil-fuel based economies to embracing clean energy alternatives so as to minimise environmental pollution and reduce carbon footprint. India, too, in line with its global peers, has set ambitious targets for the clean energy sector, as it aims to meet 40 percent of its total energy needs through renewable energy by the year 2030.

A look at the current technologies for energy storage
Various renewable energy sources are now gaining popularity such as solar, wind, and hydropower. Parallelly, safe, reliable and efficient energy storage technologies with the capability to be utilised on a large scale are being deployed to power end-user applications. When it comes to batteries to run portable electronic devices and electric vehicles (EVs), lithium-ion batteries (LIBs) have gained huge traction in the market as of now. However, the energy density of state-of-the-art LIBs is seen to be approximately 200 Wh/kg, which is mostly inadequate to fulfil the demands of high-energy and power density-based EVs.

Here are a few other issues with the large-scale application of LIBs:
● Lithium-ion based systems are highly unsafe as they are prone to explosion.

● Further, these systems have very limited energy density and thus cater to a range of approximately 150-250 km for EVs, becoming a major bottleneck for EV adoption of LIBs.

● Lithium is a scarce mineral and hence it is not a sustainable option in the long run. Also, LIBs are costly because of the presence of rare minerals like lithium, cadmium etc. as well as due to high-end manufacturing requirements. As a matter of fact, India does not have any lithium reserves of its own, and thus will have to be import-dependent.

● These batteries are very difficult and expensive to recycle, and even after recycling, the metal extracted is not suitable to be used again in batteries. Thus, majority of the used batteries end up in landfills.

● Last but not the least, these batteries have a limited cycle life. This implies that their cost to the end consumer at a total ownership level is expected to increase exponentially in the times to come.

Even if the above issues are neglected and the EV and/or clean energy ecosystem becomes highly dependent on Li-ion batteries, setting up charging infrastructure to complement the same would account for a huge expense on the part of the government. Also, in the long run, given the humongous energy demand projected only for EVs in India, it is expected that thermal will remain as the leading source of energy at large.

Keeping these hiccups in mind, a need has been felt lately to adopt clean energy generating solutions rather than mere energy storage solutions. Hydrogen fuel cell is one such solution for energy generation that has existed in the market for many years now. This technology converts hydrogen (which acts as a fuel) into electricity.

To be precise, there are two major issues that have slowed down the adoption of hydrogen fuel cells across the globe:
● Exorbitant capital cost: Even after prolonged research since the early 20th century, the cost of hydrogen fuel cell is still too high till date.

● Safety: Hydrogen is explosive in nature. This is why it is used to make bombs. This further makes the concept unsafe for commercial/individual use.

Even with these issues and concerns, countries like Japan, South Korea and many European countries are adopting the hydrogen economy, wherein a large solar/wind park is made to generate energy in a clean manner. This electricity is used to generate hydrogen which is then transported to various endpoints like fuel stations for applications like stationary power backup and EVs. Japan currently has more than 2,50,000 fuel cell power backup solutions installed in the country. The reason for this mass adoption and push by the respective governments is that a hydrogen fuel cell based economy solves the issues mentioned with the lithium-ion based electric economy, and is a much better long-term sustainable option.

Applications of aluminium–air batteries
Now, this is where aluminium–air battery comes in, bringing in the best of both worlds. It not only solves the issues for Li-ion batteries, but also overcomes immediate and long-term obstacles faced by the hydrogen fuel cell economy. Aluminium–air batteries have gained great interest in recent times due to their high energy density (can go up to 8,000 Wh/kg), low cost (roughly 1/10th as compared to hydrogen fuel cells) and being the safest compared to the two mentioned above. It basically uses aluminium and water, combined with a graphene-based novel cathode, to harness electricity/energy in a much higher capacity as compared to Li-ion. The system contains around 60 percent water and is thus safe to use. It is similar to a hydrogen fuel cell in broader principle, except that in place of hydrogen, aluminium is used as a fuel.

A sustainable and scalable solution for India
There is a huge potential of using aluminium–air battery as an alternate to hydrogen fuel cells, and there is no doubt that it can act as a more sustainable and easily adoptable solution when compared to Li-ion battery based systems. Not only can this provide India specific advantages of being low-cost and indigenously produced, but is also safe in terms of mass handling.

We, at Log 9 Materials, are constantly striving to push this technology for stationary and mobility applications. At this juncture, access to capital (for further research on the application and commercialisation of aluminium–air batteries) and government support to push this technology through pilot projects with its various arms like the telecom segment can help this technology make the country generate energy in a cleaner way, for longer durations as well as at affordable prices.

India did miss the bus on hydrogen fuel cell, but we do believe it was for the better, as we now have a safer, affordable, and scalable solution sitting with us, ready to be pushed forth for good.

Authored by:
Kartik Hajela,
Co-Founder,
Log 9 Materials