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Are supercapacitors a viable alternative to batteries?

Updated: Dec 30, 2021

As discussed in our previous blog posts, fast charging and intense use can cause a lot of stress to batteries. This makes them dangerous and reduces their life cycle - thereby making heavy-duty battery-based energy storage expensive, unsustainable and even unsafe.

How are supercapacitors different from batteries?

An alternative approach is the use of supercapacitors (also known as ultracapacitors). Unlike batteries that store energy through reversible chemical reactions, supercapacitors rely on electrostatic separation of charged particles in the electrolyte - a phenomenon akin to the build-up of electricity on your woolen sweater. Electrostatic energy storage allows for very fast charging and even faster discharge. The number of charge cycles is virtually unlimited, but the amount of energy that can be stored is proportional to the surface area of electrodes and is much lower compared to batteries.

Why they are relevant - and why they are not

While the first electrochemical battery was demonstrated by Alessandro Volta more than two centuries ago, the supercapacitors are a relatively young technology. In 1982, the first devices were introduced for military applications and immediately became a hot R&D topic, anticipated to become the next big thing in the energy storage industry. Years of R&D led to the creation of really advanced devices that are extremely fast to charge and last 100 times longer than batteries. Heck, Elon Musk was even going to do a PhD on supercaps (see here)

Unfortunately, however, supercapacitors still have two main problems that remain since their inception: they can store 10-50 times less energy per kilo/liter than batteries (i.e. they are very bulky) and they are very expensive. As a result, the supercap industry has never really been thriving. Then li-ion came into the picture. Thanks to the versatility of this great technology, it solved a lot of the problems for which supercaps have been eyed for.

Insatiable demand for high-power storage

However, in the recent years there's been quite an uptick in the interest for high-power energy storage, supercapacitors included. Many partnerships have been announced between big corporates and supercap companies (e.g. Skeleton Technologies), and the industry leader, Maxwell Technologies, was acquired by Tesla in 2019. The reason for this development is the level of electrification that has been reached by now: pure-play integrations of li-ion batteries have pushed it quite far, but have reached kind of a glass ceiling (going forward, electrifying more challenging cases is getting increasingly more expensive, more dangerous, and unacceptably unsustainable). Therefore, engineers are looking for heavy duty solutions with the capability of hundreds and millions of high-power (i.e. very fast, seconds-to-minutes) charge-discharge cycles.

So does that mean that supercaps are back in the spotlights as the next big thing? Unfortunately, not quite. Further advances in pure-play supercapacitor technology are making them even more expensive and there are still no devices on the market with acceptable energy densities to make them viable for mass-market applications like, say, hybrid vehicles. Companies are trying to introduce highly complex nanotechnology processes to push their capabilities further, but they make the resulting devices more and more exotic. This is somewhat similar to Elon's results back in Stanford where they ended up with a great device (quite high energy, i.e. not too bulky) but manufactured with the use of way too rare and expensive materials. Besides that, supercaps are reliant on the same highly flammable and toxic electrolyte solvents as li-ion batteries. This compromises the safety or over-complicates the energy storage systems where they are put to use.

Hybrid solutions: the holy grail of energy storage

The team behind Geyser Batteries has been in the supercapacitor business since the 90s. The supercaps we produced had a great advantage: they were using water as a solvent, making them completely safe and very reliable even in extremely harsh environments. Customers loved the products for high power and reliability, but we were never happy about how small an amount of energy our devices could store.

Then innovation happened: we figured out how to introduce a typical battery energy storage mechanism based on simple electrochemical reactions to our safe supercapacitors without losing a single bit of supercapacitor qualities - all while slashing its price.

At that point, Geyser Batteries was launched to bring this principally new device to the market. We not-so-humbly pride ourselves of deliver the holy grail of the energy storage industry: a device that can be recharged millions of times, is very fast, and can store an amount of energy that is - even in the early days of this technology - five times higher than supercaps and on-par with comparable high-power li-ion solutions.


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