NiSalen-Based Batteries Charge 10 Times Faster Than Lithium-Ion — But Energy Density Lags Behind
Novel battery material, in development since 2016, charges considerably faster — but work remains to get the energy density up.
A team of researchers from the St. Petersburg State University have come up with a new type of battery which, they say, can be charged at a rate some 10 times faster than traditional lithium-ion equivalents — using a NiSalen polymer.
"We came up with the concept of this material in 2016. At that time, we began to develop a fundamental project, 'Electrode materials for lithium-ion batteries based on organometallic polymers,'" explains Professor Oleg Levin. "It was supported by a grant from the Russian Science Foundation.
"When studying the charge transport mechanism in this class of compounds, we discovered that there are two keys 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. And secondly, they can be used as an active component of electrochemical energy storage materials."
Over the next three years, the team worked on refining a polymer based on the nickel-salen complex (NiSalen) and to which energy-intensive nitroxyl "pendants" could be attached. The result: A battery material with an extremely high capacitance.
"A battery manufactured using our polymer will charge in seconds - about ten times faster than a traditional lithium-ion battery," Levin claims. "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 percent 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."
The team's latest work on the topic, which proved 66 percent capacity retention after 2,000 charge-discharge cycles, has been published under closed-access terms in the journal Batteries & Supercaps.