New nanolithia cathode battery does not ‘breathe’ oxygen
A NEW battery concept, called a nanolithia cathode battery, is described in the journal Nature
Energy in a paper by Ju Li, the Battelle Energy Alliance Professor of Nuclear Science and Engineering at MIT; postdoc Zhi Zhu; and five others at MIT, Argonne National Laboratory, and Peking University in China.
In the paper Li explains a major shortcoming of lithiumair batteries is difference in voltages between charging and discharging, with the output voltage 1,2 or more volts lower than the charging voltage.
This means 30% of the electrical energy is lost as heat during charging, said Li. Conventional lithium-air batteries draw in oxygen to drive a chemical reaction with the battery’s lithium during the discharge cycle, and release the oxygen during the charging cycle. In the new battery, the same electrochemical reactions between lithium and oxygen take place during charging and discharging, but the oxygen stays inside the battery and transforms directly between its three redox states, while bound in the form of three different solid chemical compounds, Li2O, Li2O2, and LiO2, which are mixed together in the form of a glass. Li said the new battery loses only eight percent of the electrical energy as heat. “This means faster charging for cars, as heat removal from the battery pack is less of a safety concern, as well as energy efficiency benefits,” Li said.
The new battery is also inherently protected from overcharging, as the chemical reaction is self-limiting. “With a typical battery, if you overcharge it, it can cause irreversible structural damage or even explode,” Li said, adding they overcharged the battery for 15 days, to a hundred times its capacity, but there was no damage at all.