Chinese scientists are stepping up research on dual-ion battery, attracted as they are by the advantages of high working voltage, high safety, and low cost of such battery.

Dual-ion battery features higher efficiency, thanks to participation in reaction of both anion and cation, different from conventional lithium-ion battery, in which lithium-ion moves between cathode and anode in operation.

Shenzhen Institute of Advanced Technology (SIAT), Chinese Academy of Sciences, is a vanguard in this field, having developed dual-ion battery with low-cost and more accessible high-conductive graphite as the material for cathode, in place of licoo2 and lithium iron phosphate.

The SIAT research team points out that when the new battery is discharging, intercalation reaction will take place at cathode, as anion would be embedded on cathode via ion-channel in electrolyte, boosting working voltage. During the process of charging and discharging, anion and cation would separate and reunite via the medium of electrolyte, just like the bridge formed by magpie in Chinese folklore which enables the cowherd and the waver maid to meet during the Double Seventh Festival.

The technology marks a new breakthrough in dual-ion battery technology, with significant improvement in stability, following the development of aluminum-graphite dual-ion battery by a research team lead by Tang Yongbin of the Chinese Academy of Sciences in 2016. Compared with conventional lithium-ion battery, the latter significantly reduces the size and cost of battery, in addition to improving the transmission efficiency of ion and electric charge.

To overcome the problem of concentrated stress caused by the swelling of aluminum electrode, the Tang Yongbin team developed a brand new aluminum anode via joint deposition of active material aluminum and non-active material copper, greatly enhancing the stability of electrode. The team reports that the battery can still keep 88% of capacity, following 200 times of charging and discharging.

Meanwhile, the SIAT team has started research on environment-friendly low-cost sodium dual-ion battery and calcium dual-ion battery boasting even higher working voltage.

(Collaborative media: TechNews, first photo courtesy of Chinese Academy of Sciences)