Researchers in Australia have unveiled a working prototype of a “proton battery” that they say could eventually overtake lithium-ion as a more powerful and sustainable alternative.
The Melbourne RMIT University team said potential applications for the proton battery include home energy storage devices charged from solar panels and electric vehicle charging.
The researchers, whose studies have been part funded by the Australian Defence Science and Technology Group and the US Office of Naval Research Global, said the prototype uses a carbon electrode as a hydrogen store, coupled with a reversible fuel cell to produce electricity.
According to the team, during charging, the carbon in the electrode bonds with protons generated by splitting water with the help of electrons from the power supply. The protons are released again and pass back through the reversible fuel cell to form water with oxygen from air to generate power.
“Unlike fossil fuels, the carbon does not burn or cause emissions in the process,” the team said.
Experiments showed that the small proton battery, with an active inside surface area of only 5.5 square centimetres (smaller than an Australian 20 cent coin), “was already able to store as much energy per unit mass as commercially-available lithium ion batteries”. This was before the battery had been optimised, the team said.
Results showed that a porous activated-carbon electrode made from phenolic resin was able to store around 1 wt% hydrogen in the electrode, the team said. “This is an energy per unit mass already comparable with commercially-available lithium-ion batteries, even though the proton battery is far from being optimised. The maximum cell voltage was 1.2 volt.”
Lead researcher Professor John Andrews said: “It’s the carbon electrode plus protons from water that give the proton battery it’s environmental, energy and potential economic edge.”
“Our latest advance is a crucial step towards cheap, sustainable proton batteries that can help meet our future energy needs without further damaging our already fragile environment,” Andrews said.
“Future work will now focus on further improving performance and energy density through use of atomically-thin layered carbon-based materials such as graphene, with the target of a proton battery that is truly competitive with lithium ion batteries firmly in sight,” Andrews said.
“Powering batteries with protons has the potential to be more economical than using lithium ions, which are made from scare resources,” Andrews said. “Carbon, which is the primary resource used in our proton battery, is abundant and cheap compared to both metal hydrogen-storage alloys, and the lithium needed for rechargeable lithium ion batteries.”
Details of the RMIT research have been reported in the International Journal of Hydrogen Energy.