Ligna Energy was established with a commitment to revolutionise the creation and application of products that store electric energy, with sustainability being at the very heart of the company’s priorities.
Ligna Energy has developed bio-based and high-quality energy storage solutions to address the rapidly growing demand for energy in a world that’s rapidly embracing a digital transformation and is being changed dramatically in the process.
The company has developed a range of sustainable supercapacitors and, last year, released a new compact product, the 50mF S-Power 2R. It provides a combination of rapid charging and reliable output characteristics that are required for use in portable systems that are powered by ambient RF energy and has been made entirely from sustainable, non-toxic, and easily recyclable materials.
According to the company it contains only aluminium as its metal component and activated carbon made from recovered biomaterials.
“This is a truly innovative design with a significantly lower environmental footprint than is the case when compared to the materials typically used in conventional supercapacitors,” explained John Söderström, Marketing Director at Ligna Energy.
Measuring just 20x 20mm the 2R supercapacitor has a maximum thickness of just 0.4mm and is intended for use in slim form factors such as smart cards or tracking tags.
“One of the most important aspects of the S-Power device is its thin form factor and with an aluminium laminate pouch it provides much greater design flexibility than traditional cylindrical supercapacitors,” said Söderström, adding, “It can even be applied to curved surfaces, and we’ve demonstrated its flexibility or bendability through extensive testing. For example, we tested it with a credit card up to a 1000 times with no discernible degradation in performance levels.”
The supercapacitor’s ESR of 2.5Ω and long life of more than 100,000 cycles make it suitable for NFC and RFID applications in which the electronic circuitry is powered by the energy harvested from a reader’s RF field. Operating at a rated voltage of 2.7V when fully charged, the 2R also provides energy store for devices powered by ambient light, such as wireless sensors or remote controls.
Over the past couple of years Ligna Energy has been working with a number of companies and advances in energy-harvesting technology and PMICs means that with its thin supercapacitors it’s possible to create much smaller devices, that are not only cheaper to manufacture but also easier to integrate into everyday environments.
By using smaller devices fewer materials are used, which has a ripple effect on sustainability.
Above: Ligna's 2R device comes in an ultra-thin form factor but delivers excellent electrical performance
A classic spinout
“Ligna Energy is a classic spinout company from research conducted at Linköping university here in Sweden,” explained Söderström. “The company’s initial focus was on developing ‘big batteries’ capable of storing energy from solar or windmill parks. However, in 2021 the company took the decision to focus its attention towards thin and small bio-based supercapacitors for small connected electronic devices.
“The decision to refocus was a consequence of realising that it would be just too expensive to build prototypes using the material techniques that had been developed. The technology was also immature, so we made the decision to pivot to smaller devices and from batteries to capacitors.”
A supercapacitor, which is also known as an ultracapacitor or electric double-layer capacitor (EDLC), is an energy storage device that bridges the gap between conventional capacitors and batteries and unlike batteries they can store energy electrostatically.
“Supercapacitors offer much greater versatility for designers due to their simpler, more robust construction. And as we’ve demonstrated with our 2R device they can be more flexible and can be adapted into thin-film technologies more readily than batteries,” Söderström explained.
“They also support rapid charging which makes them suitable for applications that require quick energy replenishment. However, energy density is typically lower than that of batteries, which does tend to limit their use for long-term energy storage.”
Söderström also points out that while the company’s devices are similar to conventional supercapacitors they also offer improved safety and a reduced environmental footprint and can be paired with an energy harvester.
The company’s first products appeared in 2023 with the 2S release which represented a significant improvement on its existing supercapacitor technology, offering more than double the energy capacity compared to the first products the company had developed and making it suitable for a much wider range of applications. Crucially, the S-Power 2S was designed to be thinner and almost half the size of its predecessor, making it suitable for space-constrained applications.
The 2R, described above, takes that technology even further and is likely to appear on the market once an extensive evaluation process is completed.
“While we have focused on supercapacitors, we are still developing battery technology as we’ve found that clients are interested in an environmentally friendly battery, in the same flexible shapes that we can provide for supercapacitors, using our roll-to-roll manufacturing capabilities,” said Söderström.
Ligna Energy's products contain none of the toxic chemicals found in competing products and are 100% safe to recycle or dispose of.
In addition, the choice of materials in Ligna Energy's products is made with the aim of maximising the scope for recycling at the end of the host product’s life and minimising the device’s carbon footprint.
“It’s fair to say that no other supercapacitor can get anywhere close to our S-Power products in terms of sustainability, non-toxicity, and our use of green, bio-based materials,” Söderström claimed.
“Once our 2R device comes to market we will be able to support manufacturers of smart cards, NFC tags and other RF energy-based products helping them to make their products greener while benefiting from the 2R’s ultra-thin form factor and excellent electrical performance.”
Ligna Energy is well established in Sweden, where it has been voted as one of the country’s Top 33 tech companies.
“We’re certainly well known in Sweden, but we're now gaining traction abroad. While we attended electronica last year, we also went to Embedded World which delivered real progress in terms of partnership development and client interaction,” said Söderström.
When it comes to partnerships Ligna Energy has been working with a variety of companies.
“With the 2S we are see it being used where you need to store a few days of energy – indoor climate controls, proximity sensors and the like – sensors that are not too power consuming or complex and they could be deployed in the smart home or in retailing,” according to Söderström.
“Shelf labelling could prove to be a very big market for us as almost all the ESLs deployed today use some form of lithium battery with coin cells being the primary power source – they may be convenient, but they will need to be replaced at some point in the product life. I’d be keen to see energy harvesting technology and our supercapacitors being used to replace them.”
Looking to the future this year feels like a key one for the company.
“Producing hardware is time consuming. Testing and evaluation of our products has been extensive and is ongoing, but what we are planning for in 2025 is to see our products launched commercially with a number of select customers,” concluded Söderström.
