New type of battery charges ten times faster than lithium-ion

A research team from St. Petersburg State University have been exploring the use of “redox-active nitroxyl” containing polymers as materials for electrochemical energy storage.

These polymers have a high energy density and fast charging and discharging speeds due to what is known as fast redox kinetics. However, the implementation of this technology has proved challenging due to their insufficient electrical conductivity, which impedes the charge collection.

The team overcame this limitation by synthesising a polymer based on the nickel-salen complex (NiSalen). The molecules of this metallopolymer act as a molecular wire to which energy-intensive nitroxyl pendants are attached.

The molecular architecture of the material enables high capacitance performance to be achieved over a wide temperature range.

“We came up with the concept of this material in 2016,” said researcher Oleg Levin. “When studying the charge transport mechanism in this class of compounds, we discovered that there are two key directions of development.

“Firstly, these compounds can be used as a protective layer to cover the main conductor cable of the battery, which would be otherwise made of traditional lithium-ion battery materials. Secondly, they can be used as an active component of electrochemical energy storage materials.”

The polymer took over three years to develop, which included the creation of several different polymers. Only one was ultimately found to be sufficiently stable and efficient.

“A battery manufactured using our polymer will charge in seconds; about ten times faster than a traditional lithium-ion battery,” Levin said.

“This has already been demonstrated through a series of experiments. However, at this stage, it is still lagging behind in terms of capacity: 30 to 40 per cent lower than in lithium-ion batteries. We are currently working to improve this indicator while maintaining the charge-discharge rate

“The new battery is capable of operating at low temperatures and will be an excellent option where fast charging is crucial. It is safe to use: there is nothing that may pose a combustion hazard, unlike the cobalt-based batteries that are widespread today.

“It also contains significantly less metals that can cause environmental harm. Nickel is present in our polymer in a small amount, but there is much less of it than in lithium-ion batteries.”

Last year, an Israeli battery company said it had developed an ultra-fast battery charging solution designed to be used to charge commercial drones in just five minutes.