Enhancing today's batteries: bridging the gap to solid-state

Battery technology development is today attracting global media attention on a scale that has in the past only been rivalled by significant advances in medical science. This is because better battery technology will open the door to a substantial shift in how societies approach mobility, how renewable energy systems are deployed and integrated into existing electricity grid infrastructures, and the design and performance of personal electronic devices. These potential impacts are huge, but most important of all, they will also have a profound effect on our collective efforts to limit the environmental impact of human-induced climate change.

Across the globe, academic and research institutions, car companies, battery manufacturers and a whole host of other commercial organisations are focusing a lot of attention on improving the performance of batteries. A particularly important area of this endeavour is solid-state battery technology, which, maybe surprisingly, was first discovered by the English scientist Michael Faraday in the 1830s. For many years, this technology attracted little attention, but in recent years, all that has changed as industry and academia have recognised that the fundamental advantages of solid-state technology, once harnessed and commercial, should deliver significant performance improvements over and above existing liquid electrolyte battery technology.

However, solid-state battery technology is challenging, with many different electrolyte candidates being worked on and developed. All must overcome solid electrolytes' challenging conductivity issues, which lead to low-rate performance, high internal resistance, slow charging speeds and high cost. However, solid-state batteries hold much promise because of their potential advantages over existing liquid electrolyte technology, including higher energy densities and consequently smaller cell size, significantly longer cycle life and improved safety because of the reduced risk of leakage or combustion. Solid-state batteries are also potentially substantially more environmentally friendly than existing lithium-ion batteries. Some studies suggest their climate impact on a like-for-like basis, compared to lithium-ion batteries, could be reduced by nearly 40%.

For the time being, because of the many challenges confronting the development of viable, commercial, solid-state battery technology, they have only been deployed in small volumes in niche markets, especially where safety is a paramount issue. So today, solid-state batteries can only be found in pacemakers, other wearable devices and some RFID systems.

In recent weeks, much media attention has been paid to some interesting claims emerging from very large organisations about solid-state battery technology. So, for example, this week, the Financial Times reported that Toyota, the world’s largest volume car manufacturer, had claimed that it is close to manufacturing next-generation solid-state batteries at the same rate as existing batteries for electric vehicles. Later in the article, it became clear that “close” meant by 2028, but nevertheless, this is a bold claim. Not least because, as Goldman Sachs has pointed out in various publications on the subject, producing solid-state batteries in large volumes is costly and complex in part because it will require new process equipment capable of high volume through-put to be both designed and installed. There are also well-known problems with early versions of the batteries, including their sensitivity to moisture and oxygen and the mechanical pressure required to hold them together to prevent the formation of metal filaments in the batteries that can cause short circuits.

Other bold claims have also been made in recent years about how quickly solid-state battery technology and the manufacturing infrastructure required to make them would be in place, only for those claims to be disappointed by delays and new challenges. Some companies have also claimed to have designed and built a solid-state battery, but the reality is that these have replaced the liquid electrolyte with a gel, which we don’t consider to be a true solid-state battery. Indeed, Sony was producing polymer (gel) cells some twenty years ago, so this is not a new technology at all.

On closer inspection, it emerges that Toyota’s president, Koji Sato, has admitted that “production volumes of solid-state batteries are likely to be small to begin with,” which speaks to the known challenges of not only building a commercially viable solid-state battery but also making it in the volumes required to supply a very large industry. Finally, Toyota is known to be working with another Japanese business, Idemitsu Kosan, to develop its solid-state electrolyte based on a sulphide technology that other Japanese car manufacturers are working with. These other businesses are likely neither ahead nor behind Toyota, but all are grappling with the same challenges posed by this exciting but challenging technology.

Our best guess is that the future of battery technology is solid state but that these batteries will not be widely commercially available until the early 2030s at best. This will partly be the product of the greater challenge that existing liquid electrolyte technology will pose as it evolves throughout this decade.

We believe that there are significant performance improvements to come with existing liquid electrolyte technology. For example, new silicon anode material technology being developed by a UK company called Nexeon (which has recently announced a significant commercial scale supply agreement with Panasonic and the location of its first scaled manufacturing facility in Gunsan, S Korea) when incorporated into a lithium-ion battery, can improve its energy density by up to 50%. Batteries incorporating this anode material technology will also benefit from much faster charging time.

This revolutionary technology has significant advantages over existing, traditional graphite anode technology and the silicon oxide materials currently being used in high-end EV batteries and over other silicon-based materials being developed by its competitors in North America. When battery manufacturers incorporate this technology in their products, we believe it will not only help to solve the price and range anxiety issues that have held back the EV market in many geographies but will also open up domestic, local and grid-scale electricity storage markets many of which need a step change in battery performance to become economically viable. The potential for this technology in the consumer electronics sector is also huge given, for example, the need for brighter screens, longer run times between charges and more powerful processors for faster application performance.

In summary, whether it is in the transport, energy or consumer electronic sectors, Nexeon’s silicon anode material technology has the potential to transform the performance of existing liquid electrolyte lithium-ion batteries. Consequently, over the next few years, we expect to see more global-scale battery manufacturers alongside Panasonic incorporating Nexeon’s silicon anode technology in their batteries in multiple applications.

By significantly improving the performance of this established technology, we expect that the widespread deployment of the next-generation, solid-state battery technology will be delayed until the early to mid-2030s. Still, we do see this evolution as inevitable. Crucially, Nexeon’s silicon anode materials are also compatible with solid-state battery technology and have already been trialled in a solid-state format being developed by one of the world’s leading car manufacturers with whom the business has a joint development agreement. Nexeon’s partner reported that in a qualification trial, Nexeon’s materials were the best performing of all those it had tested in the SSB format.

Battery technology will continue to capture significant media attention simply because it has such an important role in the lives of consumers, businesses and governments worldwide and in the collective priority to limit the impact of human-induced climate change. Many claims will continue to be made about how quickly solid-state batteries will become a commercial reality. Our best guess is that in focusing on this new iteration of battery technology, the media could lose sight of the significant improvements coming with existing liquid electrolyte technology. In the first instance, Nexeon’s technology will have a pivotal role to play.