Study explores the viability of realizing stable high-voltage O-redox cathodes …
To meet rising energy demands and power the countless electronic devices on the market, researchers will need to develop new advanced battery technologies. These technologies should ideally have higher energy densities and longer lifetimes, so that they can store more energy and last longer.
The energy densities of existing rechargeable lithium-ion (LiBs) and sodium-ion (NaBs) batteries have so far been difficult to increase. A key reason for this is that their cathodes, which are generally made of transition metal oxides and operate by removing and reinserting Li+ when the batteries are being charged or discharged, can only compensate charge through oxidation and reduction of the transition metal ions. This poses a limit on the overall charge that can be stored in the batteries.
Researchers at University of Oxford, University of Bath and Diamond Light Source have recently carried out a study exploring the potential of so-called “O-redox” cathodes for increasing the energy density of LiBs and NaBs. Their paper, published in Nature Energy, provides the first direct evidence of the nature of delocalized electron holes forming on O2- ions in O-redox cathodes, which could guide the future development of alternative cathodes.
“We were interested in understanding the mechanism of reversible charge storage on the oxide ions in battery cathodes,” Robert A. House, one of the researchers who carried out the study, told Tech Xplore. “There are currently only a small handful of known materials which can undergo oxygen redox reversibly and the chemistry behind this process was not clear. Revealing the nature of this charge storage mechanism could help unlock new high energy density cathode materials for the next generation of rechargeable batteries.”