We were just thinking that fuel cells could give lithium-ion batteries a run for the money when it comes to dominating the electric vehicle market of the future, when along comes MXenes, a new group of funky little atom-thin, two-dimensional materials that could keep Li-ion in the front of the pack. MXenes were discovered about three years ago by scientists at Drexel University’s A.J. Drexel Nanotechnology Institute and they’ve just announced another step in the research, so let’s take a look.
Graphene, Meet MXenes
Our obsession with graphene will have to make room for MXenes from now on. Like graphene, MXenes possess unique properties that could open up a new era of small, lighter, faster, cheaper and more efficient electronic and energy storage devices, among other things.
Loosely speaking, the structural difference is that graphene is composed of a sheet of carbon atoms arranged in a characteristic chickenwire pattern, while MXenes are composed of two layers of atom-thin materials.
Here’s the dope from Drexel:
MXenes are transition metal carbides and nitrides, created by selectively removing aluminum from layered ternary carbides known as MAX phases. Through this exfoliation process, the carbide layers are separated into two MXene sheets just a few atoms thick.
The magic happens between the sheets (sorry, couldn’t resist. will try harder next time), because MXenes can host “guest” ions and molecules between their layers. In the case of lithium ions, that would result in a significant boost for Li-ion battery performance. In addition to improving Li-ion batteries, the research could zlxo lead to other kinds of metal-ion advanced batteries.
So far, the team has developed eight MXenes with sodium, magnesium, potassium, ammonium and aluminum ions in addition to lithium.
The team’s latest results, which are published in the journal Nature Communications, also indicate that a flexible, paperlike MXene electrode could substitute for conventional, bulkier rolled powder electrodes, leading to the development of lightweight, wearable batteries. That includes obvious military applications for wearable energy storage.
In the meantime, let’s not forget that graphene is still in there kicking, one recent development being a graphene supercapacitor that could replace Li-ion batteries in electric vehicles.