In a potential technological leap that most scientists remain skeptical about, a Japanese paper producer is determined to pursue a strategy of using trees to develop a successor to lithium-ion batteries for electric cars.
Nippon Paper Industries, the Japanese paper manufacturing company is targeting new breakthroughs in the use of cellulose nanofibers with the aim of creating supercapacitors that could store and release energy with significantly improved performance and less environmental impact than existing batteries.
Cellulose nanofibers are materials produced by refining wood pulp to the size of a hundredth of a micron or less, and are currently used in products like diapers or food additives.
“We need to work faster with other companies to find practical uses,” Toru Nozawa, CEO of Nippon Paper, said. Nanofiber cellulose-based supercapacitors, or CNFs, could “be applied in areas where lithium-ion batteries are used, such as cars and smartphones by 2025, and fully commercialize the technology a decade later.”
Supercapacitors retain massless electrons in an electric field, while batteries store energy in chemical form. The differences mean the former are ideal for delivering short, intense bursts of power, like the pop of a camera flash, but only have a fraction of the storage capacity of a lithium-ion battery.
For decades, this means that supercapacitors have played a role in niche applications, used in memory backup systems for laptops, pitch control for wind turbine motors, or in regenerative braking for certain hybrid and plug-in vehicles. They also delivered on the long unfulfilled promise of an energy storage system with significantly shorter recharge times, fewer safety risks, and zero reliance on expensive metals like cobalt or nickel.
“There are lots of opportunities for supercapacitors to continue to grow as a technology, but they are in a completely different technology segment versus batteries,” said experts. “Supercapacitors are not and never will be a competitor to lithium-ion batteries.”
Challenges and possibilities are numerous
There’s also a challenge from improvements to existing lithium-ion batteries, which have routinely provided good energy storage capacity, but have previously found slow recharging a limitation. Now, some battery technologies offer 30 minute charging times, and companies including American vehicle maker Volkswagen are aiming to cut that duration to about 12 minutes, said analysts.
Meanwhile, supporters of supercapacitors insist there’s value in persevering. Energy density is already improving, and the components can take another major step forward by using cellulose nanofiber, known as CNF, said Mikio Fukuhara, a research fellow at Tohoku University who has collaborated with Nippon Paper.
In a paper published in March in the journal Nature, a team of scientists including Mr. Fukuhara offered evidence that supercapacitors using CNFs could be used to store large amounts of electricity and have potential suitability for handheld electronics, transportation and for the storage of renewable energy.
Nippon Paper is also seeking opportunities to shift supply of materials to existing battery manufacturers, while it continues to develop the rival technology. The company has added at least one leading producer as a customer and is also considering plans to establish supply hubs in growing markets like Europe.
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