High-energy electrodes

A new high-energy cathode material that can greatly increase the safety and extend the lifespan of future lithium batteries has been developed through the close international collaboration of researchers led by the US Department of Energy's Argonne National Laboratory and Hanyang University in South Korea.

Developing a very high-energy system with a long calendar and cycle life and excellent abuse tolerance is an important challenge that lithium battery developers are working on to meet the energy storage needs of the light-duty vehicle market.

'The new high-energy material that we have developed makes up a new class of oxide materials in which the composition of each particle is changing from the bulk to the outer layer,' said Khalil Amine, manager of the advanced battery technology group at Argonne. 'Typically, most oxide cathodes have a uniform composition throughout each particle, and offer low capacity and high surface reactivity with the electrolyte.'

The transitional nature of the composition of this new class of oxide material gives it greater functionality.

'The basic idea behind our novel approach is to design a particle that has a very high-energy composition at the bulk and an outer-layer composition that is very stable against any reactivity with electrolyte,' added Amine. 'Those two design features will be able to significantly improve the life and safety of lithium battery materials while offering very high-energy characteristics for possible use in PHEVs.'

'The material has also demonstrated a very high-power capability,' said Yank-Kook Sun, a professor in the Department of Chemical Engineering at Hanyang University.

'We are able to charge the material to 4.3V and 4.4V and attain a very high capacity of more than 210 milliampere hours per gram, with good power capability,' he added.

Conventional cathodes have a capacity of 140mAh/g to160mAh/g.