Existing battery electrodes have low electrical, thermal and ionic conductivity, along with poor mechanical behaviour when discharged and recharged, and can also suffer from early delamination and degradation leading to safety and lifecycle issues.
The Ultra Fast Carbon Electrode
A team at the CEA (Atomic and Renewable Energy Commissariat) led by French mathematician Pascal Boulanger has developed and patented an electrode using vertically-aligned carbon nanotubes (VACNT) a derivative of graphene, making it possible to manufacture super capacitors 1,000 times faster than a lithium-ion battery.
The electrode combines the highest ionic conductivity – thanks to a 3D fully accessible nanostructure – with the highest electrical and thermal conductivity, provided by its arrangement of 100 billion nanotubes per sq. cm, all vertically aligned.
Put simply, a battery using this VACNT technology can give an electric car 800 to 1,000 km of range with only 5 minutes of recharging.
In 2014, Boulanger collaborated with Ludovic Eveillard to create a start-up called NaWaTechnologies based in Rousset, near Aix-en-Provence and the first carbon nanotube mats were made two years later.(nawa in Japanese = short string, but na(no) + wa(arming)
NaWaCap Power super capacitors offer power densities between 10 and 100 times higher than existing super capacitors.
Their Equivalent Series Resistance = ESR is more than 10 times lower. The temperature (low and high) and frequency behavior is also greatly improved and NaWaCap Power super capacitors thus make it possible to preserve more than 5 times more energy at high or low temperature or at high frequency compared to current products.
NaWa set up a subsidiary NaWa America in Dayton, Ohio, created by the acquisition of the assets of the US leader in VACNT for composite applications, N12 Technologies. Working with Dr. Paul Kladitis’ Multifunctional Structures and Materials at the University of Dayton Research Institute (UDRI), with Laboratory, NaWa America has developed NaWaStitch, a thin film made of hundreds of billions of carbon nanotubes all aligned vertically which serves as an interface between the folds of composite materials and like a “nano-velcro” mechanically reinforces this interface.
NaWa America has also signed an exclusive license agreement with the Massachusetts Institute of Technology (MIT), and the work of the research laboratory of Professor Brian Wardle (NECSTLAB), well known in the fields of composites and nanotubes.
In February 2020 NaWaTechnologies in France raised €13 million to build next-generation production line equipment at Rousset by 2021, allowing NaWa to steadily build up to over 100,000 ultracapacitor cells per month when at full capacity. The integration of this technology for future urban mobility, including electric buses, trams or autonomous vehicles is estimated at around 2024/2025.
At the 2020 Consumer Electronics Show (CES) in Las Vegas, as proof of concept, NaWaTechnologies revealed its 150 kg NAWA Racer concept e-bike which debuted their NaWaCap innovation.
The bike’s 9kWh lithium-ion battery can capture 80% more energy by regenerative braking. The smaller battery is mounted low in the chassis and will weigh around 10kg, much less than current electric sportbike batteries.
This gives the NAWA Racer a 300km (186 miles) range for inner-city riding, while recharging in just 2 minutes or an 80% entire battery charge in one hour.
NaWa Technologies is also developing a concept called NaWaShell, an integrated structural hybrid battery that incorporates VACNT to give two complimentary characteristics: enhanced mechanical strength and electrical energy storage within the core of the composite structure.
NaWa’s dry electrode technology also brings significant environmental advantages, being easily recyclable and eco-disposable at the end of its long lifecycle. As a result, NAWA estimates that by using an Ultra Fast Carbon Electrode in lithium battery cell, the CO2 footprint could be reduced by as much as 60%, simply because less active material is required.
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