• Prototype of electric moped with 90-second charge time set to hit the streets in 2022
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Prototype of electric moped with 90-second charge time set to hit the streets in 2022

The secret sauce is a novel lithium-carbon battery chemistry.
By Jason Deign

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Allotrope's technology would suit a wide range of small vehicles, including e-scooters. (Allotrope Energy/Mahle Powertrain)

A prototype battery-powered moped that can recharge in as little as 90 seconds could be on the road next year. 

The vehicle will be used to test a novel lithium-carbon battery developed by U.K.-based Allotrope Energy and unveiled in September by Mahle Powertrain, a British subsidiary of one of the world’s largest automotive suppliers.

The fast-charging capacity is a result of the lithium-carbon battery’s high specific power, which tops 15 kilowatts per kilogram, according to Allotrope. This compares to a maximum of around 10 kW per kilogram for other lithium-ion chemistries.

The fact that lithium-carbon batteries had not already been developed might seem odd given the battery industry’s keenness for novel chemistries. The holdup was because an essential component of the chemistry, nanoporous carbon, only recently began being used in battery development, said Pete Wilson, Allotrope’s technical director.

Nanoporous carbon has traditionally been categorized as a capacitor material, Wilson said in an interview. 

Since the capacitor industry is smaller and slower-moving than the battery sector, the potential of nanoporous carbon went unnoticed for a long time, he said. 

A chance discovery brought about by an unusual request

This changed in 2014 when a German automotive company came to the Allotrope team, which was then focused on capacitors, in search of a new battery technology. 

We realized that the battery they were asking for was not an ultracapacitor and it wasn’t a lithium-ion battery, but some bizarre combination of both,” said Wilson. 

When we did the basic mathematics on why this battery had not been commercialized, it became clear the reason is this problem with the carbon. We were a company that specialized in carbon. As a result, we put all the pieces together.”

Lithium-carbon is well suited to electric mopeds because the vehicles and their charging requirements are relatively simple, Wilson said. It is quite easy to build a lithium-carbon battery to replace the ferrous phosphate or lead-acid products used today.

A lithium-carbon battery (Allotrope Energy/Mahle Powertrain)

In theory, the battery could be fully charged in just 60 seconds. The 90-second charging time is due to the limitations of charging infrastructure rather than the battery. 

The reason why it’s a 90-second charging concept is because Mahle designed a prototype buffered chargepoint. The charger has a battery inside it and the battery dumps its energy into the moped,” Wilson explained.

For the larger batteries used in electric cars, there simply isn’t enough grid capacity to cope with lithium-carbon batteries. That’s why it’s unlikely the chemistry will be scaled up for larger vehicles.

Alternative use cases for fast-charging batteries

Wilson thinks it would make more sense for electric cars to use hybrid lithium-ion battery and ultracapacitor systems that can be charged within five minutes using 350-kilowatt charge points.

Despite this, there are several other potential applications for lithium-carbon beyond mopeds. 

Wilson said Allotrope is also in talks with charging station operators about creating battery-backed buffers for electric vehicle charging systems, as well as maritime industry players regarding the delivery of energy at ports and quays.

The technology could also be used to shorten the charging time needed for last-mile delivery vehicles and autonomous guided vehicles such as automatic forklifts, he said. 

A chemistry that avoids cobalt supply problems

Beyond its high specific power, another advantage of the lithium-carbon chemistry is that it does not use cobalt or nickel, two elements that pose supply-chain concerns in some other lithium-ion battery types.

Cobalt, in particular, is limited in availability, and most of today’s supplies come from the Democratic Republic of Congo, where the rights and welfare of independent miners are a cause for concern.

You could not electrify all the cars in this world with cobalt — we simply don’t have enough,” said Wilson. 

Raw materials are becoming a problem for the battery industry as electric vehicle demand rises. Ganfeng Lithium and BYD both announced price increases in October, China Daily reported.

BYD is pulling out of the grid-storage business altogether to concentrate on vehicle manufacturers,” said Hugh Sharman, senior sales consultant for Eos Energy Storage, a non-lithium utility-scale battery maker.

There simply isn’t” enough material to go around, he said. Even natural graphite suitable for [use in the manufacture of] batteries is scarce.”

Jason Deign reports on global trends in climatetech, energy storage and wind. He is based in Barcelona, Spain.