A team from the Shenzhen Institutes of Advanced Technology (SIAT) of the Chinese Academy of Sciences has developed a novel, environmentally friendly low-cost battery. The new aluminum-graphite dual-ion battery (AGDIB) offers significantly reduced weight, volume, and fabrication cost, as well as higher energy density, in comparison with conventional LIBs.
The battery shows a reversible capacity of ≈100 mAh g−1 and a capacity retention of 88% after 200 charge–discharge cycles. A packaged aluminum–graphite battery is estimated to deliver an energy density of ≈150 Wh kg−1 at a power density of ≈1200 W kg−1—≈50% higher than most commercial lithium-ion batteries. A paper on the work is published in the journal Advanced Energy Materials.
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. According to the Freedonia Group, world battery demand is expected to rise 7.7% annually, reaching US$120 billion in 2019.
The AGDIB’s electrode materials consist of environmentally friendly low-cost aluminum and graphite only, while its electrolyte is composed of conventional lithium salt and carbonate solvent.
Compared with conventional LIBs, this battery (AGDIB) shows an advantage in production cost (~ 50% lower), specific density (~1.3-2.0 times), and energy density (~1.6-2.8 times).—Yongbing Tang, 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 Li+ ions in the electrolyte deposit onto the aluminum counter electrode to form an Al–Li alloy.
|Schematic structure of the AGDIB (Image by Professor TANG Yongbing).
The discharge process is the reverse of the charging process, where both anions and Li+ ions diffuse back into the electrolyte. Since the Al 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.
The team estimated the specific energy density and power density of the AGDIB according to the configuration of a packaged battery. Results show that the AGDIB can deliver a specific energy density of ~222 Wh kg−1 at a power density of 132 W kg−1, and ~150 Wh kg−1 at 1200 W kg−1. Compared with commercial LIB (~200 Wh kg−1 at 50 W kg−1, and ~100 Wh kg−1 at 1000 W kg−1) and electrochemical capacitors (~5 Wh kg−1 at 5000 W kg−1), the AGDIB showed significantly improved performance.
The volume energy density of the AGDIB can reach ~560 Wh/L, which is much higher than traditional batteries (~350 Wh/L for Tesla Model S and ~200 Wh/L for BYD E6).
For example, a 500 kg AGDIB-based power battery could reach a recharge mileage of ~550 km (~425 km for Tesla Model S and ~225 km for BYD E6), and a 200 L AGDIB-based power battery could deliver range of about 560 km.
The AGDIB shows real potential for large-scale application in both electronic devices and electric vehicles, the researchers said.
This research was supported by the Guangdong Innovation Team and the National Natural Science Foundation of China.
Zhang, X., Tang, Y., Zhang, F. and Lee, C.-S. (2016) “A Novel Aluminum–Graphite Dual-Ion Battery.” Adv. Energy Mater. doi: 10.1002/aenm.201502588