New lightweight, efficient batteries developed by Chinese scientists

BEIJING: Chinese scientists have developed a light weight, low-cost battery which performs better than lithium ion batteries that currently power smartphones and other portable devices.

The new aluminium-graphite dual-ion battery ( AGDIB) developed by researcher of the Chinese Academy of Sciences offers significantly reduced weight, volume, and fabrication cost, as well as higher energy density, in comparison with conventional lithium ion batteries (LIB). AGDIB's electrode materials are composed of environment friendly low cost aluminium and graphite only, while its electrolyte is composed of conventional lithium salt and carbonate solvent.

The discovery is particularly important given rising battery demand and existing LIB technology, which is reaching its limit in specific energy (by weight) and energy density (by volume).

LIBs are widely used in portable electronic devices, electric vehicles and renewable energy systems. Battery disposal creates major environmental problems, since most batteries contain toxic metals in their electrodes.

"Compared with conventional LIBs, this battery (AGDIB) shows an obvious advantage in production cost (about 50 per cent lower), specific density, and energy density," said TANG Yongbing, leader of the research team.

The AGDIB mechanism follows a dual ion intercalation/alloying process.

Upon charging, anions in the electrolyte intercalate into the graphite cathode, while the lithium ions in the electrolyte deposit onto the aluminium counter electrode to form an alloy.

The discharge process is the reverse of the charging process, where both anions and lithium ions diffuse back into the electrolyte.

Since the aluminium counter electrode in the AGDIB acts as the anode and the current collector at the same time, the dead load and dead volume of the AGDIB is significantly reduced, making a battery with both high specific energy density and high volume energy density.